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1)</td></tr><tr><td>[signed] short（有符号短整型，默认）</td><td>2 字节</td><td>-32,768 (- 2^15) ~ 32,767 (2^15 -1)</td></tr></tbody></table><ul><li>② 整型：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间（内存空间）</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned int（无符号整型）</td><td>4 字节（通常）</td><td>0 ~ 4294967295 (0 ~2^32 -1)</td></tr><tr><td>[signed] int（有符号整型，默认）</td><td>4 字节（通常）</td><td>-2147483648（- 2^31） ~ 2147483647 (2^31-1)</td></tr></tbody></table><ul><li>③ 长整型：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间（内存空间）</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned long（无符号长整型）</td><td>4 字节（通常）</td><td>0 ~2^32 -1</td></tr><tr><td>[signed] long（有符号长整型，默认）</td><td>4 字节（通常）</td><td>- 2^31 ~ 2^31-1</td></tr></tbody></table><ul><li>④ 长长整型：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间（内存空间）</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned long long（无符号长整型）</td><td>8 字节（通常）</td><td>0 ~2^64 -1</td></tr><tr><td>[signed] long long（有符号长整型，默认）</td><td>8 字节（通常）</td><td>- 2^63 ~ 2^63-1</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① C 语言默认没有规定各种数据类型所占存储单元的长度，但是通常需要遵守：<code>sizeof(short int) ≤ sizeof(int) ≤ sizeof(long int) ≤ sizeof(long long)</code> ，具体的存储空间由编译系统自行决定；其中，sizeof 是测量类型或变量、常量长度的运算符。</li><li>② short 至少 2 个字节，long 至少 4 个字节。</li><li>③ 之所以这么规定，是为了可以让 C 语言长久使用，因为目前主流的 CPU 都是 64 位，但是在 C语言刚刚出现的时候，CPU 还是以 8 位和 16 位为主。如果当时就将整型定死为 8 位或 16 位，那么现在我们肯定不会再学习 C 语言了。</li><li>④ 整型分为有符号 signed 和无符号 unsigned 两种，默认是 signed。</li><li>⑤ 在实际开发中，<code>最常用整型</code>就是 <code>int</code> 类型了，如果取值范围不够，就使用 long 或 long long 。</li><li>⑥ C 语言中的<code>格式占位符</code>非常多，只需要大致了解即可；因为，我们在实际开发中，一般都会使用 C++ 或 Rust 以及其它的高级编程语言，如：Java 等，早已经解决了需要通过<code>格式占位符</code>来输入和输出变量。</li></ul></div><h3 id="_1-2-2-短整型-了解" tabindex="-1">1.2.2 短整型（了解） <a class="header-anchor" href="#_1-2-2-短整型-了解" aria-label="Permalink to &quot;1.2.2 短整型（了解）&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 无符号短整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 有符号短整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 有符号表示的是正数、负数和 0 ，即有正负号。无符号表示的是 0 和正数，即正整数，没有符号。</li><li>② 在 <code>printf</code> 中<code>无符号短整型（unsigned short）</code>的<code>格式占位符</code>是 <code>%hu</code> ，<code>有符号短整型（signed short）</code>的<code>格式占位符</code>是 <code>%hd</code> 。</li><li>③ 可以通过 <code>sizeof</code> 运算符获取<code>无符号短整型（unsigned short）</code> 和 <code>有符号短整型（signed short）</code> 的<code>存储空间（所占内存空间）</code>。</li><li>③ 可以通过 <code>#include &lt;limits.h&gt;</code> 来获取 <code>无符号短整型（unsigned short）</code> 和<code>有符号短整型（signed short）</code>的<code>取值范围</code>。</li></ul></div><ul><li>示例：定义和打印短整型变量</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义有符号 short 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;s1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hd</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // s1 = -100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义无符号 short 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;s2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // s2 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义 short 类型，默认是有符号</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">200</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;s3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hd</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // s3 = -200</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取类型占用的内存大小（存储空间）</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned short 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 2</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;signed short 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 2</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;short 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 2</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取类型的取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned short 类型的范围是[0,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, USHRT_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [0,65535]</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;short 类型的范围是[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hd</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hd</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, SHRT_MIN,SHRT_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [-32768,32767]</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><h3 id="_1-2-3-整型" tabindex="-1">1.2.3 整型 <a class="header-anchor" href="#_1-2-3-整型" aria-label="Permalink to &quot;1.2.3 整型&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 无符号整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 有符号整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 有符号表示的是正数、负数和 0 ，即有正负号。无符号表示的是 0 和正数，即正整数，没有符号。</li><li>② 在 <code>printf</code> 中<code>无符号整型（unsigned int）</code>的<code>格式占位符</code>是 <code>%u</code> ，<code>有符号整型（signed int）</code>的<code>格式占位符</code>是 <code>%d</code> 。</li><li>③ 可以通过 <code>sizeof</code> 运算符获取<code>无符号整型（unsigned int）</code> 和 <code>有符号整型（signed int）</code> 的<code>存储空间（所占内存空间）</code>。</li><li>③ 可以通过 <code>#include &lt;limits.h&gt;</code> 来获取 <code>无符号整型（unsigned int）</code> 和<code>有符号整型（signed int）</code>的<code>取值范围</code>。</li></ul></div><ul><li>示例：定义和打印整型变量</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义有符号 int 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i1 = -100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义无符号 int 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%u</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i2 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义 int 类型，默认是有符号</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">200</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i3 = -200</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取类型占用的内存大小（存储空间）</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned int 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;signed int 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;int 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取类型的取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned int 类型的范围是[0,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%u</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, UINT_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [0,4294967295]</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;int 类型的范围是[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, INT_MIN,INT_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [-2147483648,2147483647]</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><h3 id="_1-2-4-长整型-了解" tabindex="-1">1.2.4 长整型（了解） <a class="header-anchor" href="#_1-2-4-长整型-了解" aria-label="Permalink to &quot;1.2.4 长整型（了解）&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 无符号长整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 有符号长整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 有符号表示的是正数、负数和 0 ，即有正负号。无符号表示的是 0 和正数，即正整数，没有符号。</li><li>② 在 <code>printf</code> 中<code>无符号长整型（unsigned long）</code>的<code>格式占位符</code>是 <code>%lu</code> ，<code>有符号长整型（signed long）</code>的<code>格式占位符</code>是 <code>%ld</code> 。</li><li>③ 可以通过 <code>sizeof</code> 运算符获取<code>无符号长整型（unsigned long）</code> 和 <code>有符号长整型（signed long）</code> 的<code>存储空间（所占内存空间）</code>。</li><li>③ 可以通过 <code>#include &lt;limits.h&gt;</code> 来获取 <code>无符号长整型（unsigned long）</code> 和<code>有符号长整型（signed long）</code>的<code>取值范围</code>。</li></ul></div><ul><li>示例：定义和打印长整型变量</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义有符号 long 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> l1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;l1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%ld</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // l1 = -100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义无符号 long 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> l2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;l2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // l2 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义 long 类型，默认是有符号</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> l3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">200</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;l3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%ld</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // l3 = -200</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取类型占用的内存大小（存储空间）</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> l1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned long 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> l2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;signed long 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> l3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;long 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取类型的取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned long 类型的范围是[0,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ULONG_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [0,4294967295]</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;long 类型的范围是[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%ld</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%ld</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, LONG_MIN,LONG_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [-2147483648,2147483647]</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><h3 id="_1-2-5-长长整型-了解" tabindex="-1">1.2.5 长长整型（了解） <a class="header-anchor" href="#_1-2-5-长长整型-了解" aria-label="Permalink to &quot;1.2.5 长长整型（了解）&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 无符号长长整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 有符号长长整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 有符号表示的是正数、负数和 0 ，即有正负号。无符号表示的是 0 和正数，即正整数，没有符号。</li><li>② 在 <code>printf</code> 中<code>无符号长长整型（unsigned long long）</code>的<code>格式占位符</code>是 <code>%llu</code> ，<code>有符号长长整型（signed long long）</code>的<code>格式占位符</code>是 <code>%lld</code> 。</li><li>③ 可以通过 <code>sizeof</code> 运算符获取<code>无符号长长整型（unsigned long long）</code> 和 <code>有符号长长整型（signed long long）</code> 的<code>存储空间（所占内存空间）</code>。</li><li>③ 可以通过 <code>#include &lt;limits.h&gt;</code> 来获取 <code>无符号长长整型（unsigned long long）</code> 和<code>有符号长长整型（signed long long）</code>的<code>取值范围</code>。</li></ul></div><ul><li>示例：定义和打印长长整型变量</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义有符号 long long 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ll1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;ll1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lld</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // ll1 = -100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义无符号 long long 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ll2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;ll2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%llu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // ll2 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义 long long 类型，默认是有符号</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ll3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">200</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;ll3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lld</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // ll3 = -200</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取类型占用的内存大小（存储空间）</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ll1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned long long 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 8</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ll2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;signed long long 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 8</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ll3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;long long 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 8</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取类型的取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned long long 类型的范围是[0,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%llu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ULLONG_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [0,18446744073709551615]</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;long long 类型的范围是[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lld</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lld</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, LLONG_MIN,LLONG_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [-9223372036854775808,9223372036854775807]</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><h3 id="_1-2-6-字面量后缀" tabindex="-1">1.2.6 字面量后缀 <a class="header-anchor" href="#_1-2-6-字面量后缀" aria-label="Permalink to &quot;1.2.6 字面量后缀&quot;">​</a></h3><ul><li><code>字面量</code>是<code>源代码</code>中一个<code>固定值</code>的<code>表示方法</code>，用于直接表示数据，即：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 100 就是字面量</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">L</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 100L 就是字面量</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">LL</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 100LL 就是字面量</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 默认情况下的，整数字面量的类型是 int 类型。</li><li>② 如果需要表示 long 类型的字面量，需要添加后缀 l 或 L ，建议 L。</li><li>③ 如果需要表示 long long类型的字面量，需要添加后缀 ll 或 LL，建议 LL 。</li><li>④ 如果需要表示无符号整数类型的字面量，需要添加 u 或 U，建议 U 。</li></ul></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">L</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%ld\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num2 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">LL</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lld\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num3 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num4 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">U</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num4 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%u\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num4);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num4 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num5 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">LU</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num5 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lu\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num5);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num5 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num6 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">ULL</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num6 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%llu\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num6);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num6 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br></div></div><h3 id="_1-2-7-精确宽度类型" tabindex="-1">1.2.7 精确宽度类型 <a class="header-anchor" href="#_1-2-7-精确宽度类型" aria-label="Permalink to &quot;1.2.7 精确宽度类型&quot;">​</a></h3><ul><li>在前文，我们了解到 C 语言的整数类型（short 、int、long、long long）在不同计算机上，占用的字节宽度可能不一样。但是，有的时候，我们希望整数类型的存储空间（字节宽度）是精确的，即：在任意平台（计算机）上都能一致，以提高程序的可移植性。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>Java 语言中的数据类型的存储空间（字节宽度）是一致的，这也是 Java 语言能够跨平台的原因之一（最主要的原因还是 JVM）。</li><li>在嵌入式开发中，使用精确宽度类型可以确保代码在各个平台上的一致性。</li></ul></div><ul><li>在 C 语言的标准头文件 <code>&lt;stdint.h&gt;</code> 中定义了一些新的类型别名，如下所示：</li></ul><table tabindex="0"><thead><tr><th>类型名称</th><th>含义</th></tr></thead><tbody><tr><td>int8_t</td><td>8 位有符号整数</td></tr><tr><td>int16_t</td><td>16 位有符号整数</td></tr><tr><td>int32_t</td><td>32 位有符号整数</td></tr><tr><td>int64_t</td><td>64 位有符号整数</td></tr><tr><td>uint8_t</td><td>8 位无符号整数</td></tr><tr><td>uint16_t</td><td>16 位无符号整数</td></tr><tr><td>uint32_t</td><td>32 位无符号整数</td></tr><tr><td>uint64_t</td><td>64 位无符号整数</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>上面的这些类型都是类型别名，编译器会指定它们指向的底层类型，如：在某个系统中，如果 int 类型是 32 位，那么 int32_t 就会指向 int ；如果 long 类型是 32 位，那么 int32_t 就会指向 long。</p></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdint.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 变量 x32 声明为 int32_t 类型，可以保证是 32 位(4个字节)的宽度。</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int32_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x32 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 45933945</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;x32 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, x32);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // x32 = 45933945</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><h3 id="_1-2-8-sizeof-运算符" tabindex="-1">1.2.8 sizeof 运算符 <a class="header-anchor" href="#_1-2-8-sizeof-运算符" aria-label="Permalink to &quot;1.2.8 sizeof 运算符&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(表达式)</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 表达式可以是任何类型的数据类型、变量或常量。</li><li>② 返回某种数据类型或某个值占用的字节数量，并且 <code>sizeof(...)</code> 的<code>返回值类型</code>是 <code>size_t</code> 。</li><li>③ 在 <code>printf</code> 中使用占位符 <code>%zu</code> 来处理 <code>size_t</code> 类型的值。</li></ul></div><ul><li>示例：参数是数据类型</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stddef.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><ul><li>示例：参数是变量</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stddef.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(num);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><ul><li>示例：参数是常量</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stddef.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><h3 id="_1-2-9-数值溢出" tabindex="-1">1.2.9 数值溢出 <a class="header-anchor" href="#_1-2-9-数值溢出" aria-label="Permalink to &quot;1.2.9 数值溢出&quot;">​</a></h3><ul><li><p>所谓的数值溢出指的是：当超过一个数据类型能够存放的最大范围的时候，数值就会溢出。</p><ul><li>如果达到了最大值，再进行加法计算，数据就会超过该类型能够表示的最大值，叫做上溢出。</li><li>如果这个数目前是最小值，再进行减法计算， 数据就会超过该类型的最小值， 叫做下溢出。</li></ul></li><li><p>在 C 语言中，<code>整数</code>的<code>数据类型</code>分为<code>无符号</code>和<code>有符号</code>的，其在底层表示和存储是不一样的，即：</p><ul><li><code>无符号整数不使用最高位作为符号位</code>，所有的位都用于表示数值，如：对于一个 4 位无符号整数，二进制表示的范围是从 0000 到 1111 ，那么十进制表示的范围是从 0 到 15。</li><li><code>有符号整数使用最高位作为符号位</code>，这意味着它们可以表示正数和负数，通常使用补码来表示有符号整数。在补码表示法中：最高位为 0 表示正数、最高位为 1 表示负数，如：对于一个4位有符号整数，二进制表示的范围是从 0000（0） 到 0111 （7），1000 （-8）到 1111（-1）。</li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>在 C 语言中，无符号整数，最高位不是符号位，它是数值的一部分。</li><li>在 C 语言中，有符号整数，最高位是符号位，用于表示正负数。</li></ul></div><ul><li><p>对于无符号的数值溢出：</p><ul><li>当数据到达最大值的时候，再加 1 就会回到无符号数的最小值。</li><li>当数据达到最小值的时候，再减 1 就会回到无符号数的最大值。</li></ul></li><li><p>那么，无符号的上溢出，原理就是这样的：</p></li></ul><p><img src="`+t+'" alt=""></p><ul><li>那么，无符号的下溢出，原理就是这样的（需要先借位，然后再减）：</li></ul><p><img src="'+h+'" alt=""></p><ul><li><p>对于有符号的数值溢出：</p><ul><li>当数据到达最大值的时候，再加 1 就会回到有符号数的最小值。</li><li>当数据达到最小值的时候，再减 1 就会回到有符号数的最大值。</li></ul></li><li><p>那么，有符号的上溢出，原理就是这样的：</p></li></ul><p><img src="'+k+'" alt=""></p><ul><li>那么，有符号的下溢出，原理就是这样的：</li></ul><p><img src="'+e+`" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>在实际开发中，选择合适的数据类型，以避免数值溢出问题！！！</p></div><ul><li>示例：无符号的上溢出和下溢出</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> USHRT_MAX </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;无符号的上溢出 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 0</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;无符号的下溢出 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 65535</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><ul><li>示例：有符号的上溢出和下溢出</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> SHRT_MAX </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;有符号的上溢出 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hd</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // -32768</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> SHRT_MIN </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">-</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;有符号的下溢出 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hd</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 32767</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><h2 id="_1-3-浮点类型" tabindex="-1">1.3 浮点类型 <a class="header-anchor" href="#_1-3-浮点类型" aria-label="Permalink to &quot;1.3 浮点类型&quot;">​</a></h2><h3 id="_1-3-1-概述" tabindex="-1">1.3.1 概述 <a class="header-anchor" href="#_1-3-1-概述" aria-label="Permalink to &quot;1.3.1 概述&quot;">​</a></h3><ul><li>在生活中，我们除了使用<code>整数</code>，如：18、25 之外，还会使用到<code>小数</code>，如：3.1415926、6.18 等，<code>小数</code>在计算机中也被称为<code>浮点数</code>（和底层存储有关）。</li><li><code>整数</code>在计算机底层的存储被称为<code>定点存储</code>，如下所示：</li></ul><p><img src="`+r+'" alt=""></p><ul><li><code>小数</code>在计算机底层的存储被称为<code>浮点存储</code>，如下所示：</li></ul><p><img src="'+d+`" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 计算机底层就是采取类似科学计数法的形式来存储小数的，而科学技术法的表现就是这样的，如：3.12 * 10^-2 ；其中，10 是基数，-2 是指数，而 3.12 是尾数。</li><li>② 因为尾数区的内存空间的宽度不同，导致了小数的精度也不相同，所以小数在计算机中也称为浮点数。</li></ul></div><ul><li>在 C 语言中，变量的浮点类型，如下所示：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储大小</th><th>值的范围</th><th>有效小数位数</th></tr></thead><tbody><tr><td>float（单精度）</td><td>4 字节</td><td>1.2E-38 ~ 3.4E+38</td><td>6 ~ 9</td></tr><tr><td>double（双精度）</td><td>8 字节</td><td>2.3E-308 ~ 1.7E+308</td><td>15 ~ 18</td></tr><tr><td>long double（长双精度）</td><td>16 字节</td><td>3.4E-4932 ~ 1.2E+4932</td><td>18 或更多</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 各类型的存储大小和精度受到操作系统、编译器、硬件平台的影响。</li><li>② 浮点型数据有两种表现形式： <ul><li>十进制数形式：3.12、512.0f、0.512（.512，可以省略 0 ）</li><li>科学计数法形式：5.12e2（e 表示基数 10）、5.12E-2（E 表示基数 10）。</li></ul></li><li>③ 在实际开发中，对于浮点类型，建议使用 double 类型；如果范围不够，就使用 long double 类型。</li></ul></div><h3 id="_1-3-2-格式占位符" tabindex="-1">1.3.2 格式占位符 <a class="header-anchor" href="#_1-3-2-格式占位符" aria-label="Permalink to &quot;1.3.2 格式占位符&quot;">​</a></h3><ul><li><p>对于 float 类型的格式占位符，是 <code>%f</code> ，默认会保留 <code>6</code> 位小数；可以指定小数位，如：<code>%.2f</code> 表示保留 <code>2</code> 位小数。</p></li><li><p>对于 double 类型的格式占位符，是 <code>%lf</code> ，默认会保留 <code>6</code> 位小数；可以指定小数位，如：<code>%.2lf</code> 表示保留 <code>2</code> 位小数。</p></li><li><p>对于 long double 类型的格式占位符，是 <code>%Lf</code> ，默认会保留 <code>6</code> 位小数；可以指定小数位，如：<code>%.2Lf</code> 表示保留 <code>2</code> 位小数。</p></li><li><p>如果想输出<code>科学计数法</code>形式的浮点数，则使用 <code>%e</code>。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> float</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> f1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10.0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;f1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%f</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, f1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // f1 = 10.000000</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;f1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2f</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, f1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // f1 = 10.00</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 13.14159265354</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lf</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1 = 13.141593</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2lf</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1 = 13.14</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 13.14159265354</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%LF</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1 = 13.141593</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2LF</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1 = 13.14</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> float</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> f1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3.1415926</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3.14</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">e</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;f1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2f</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, f1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // f1 = 3.14</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;f1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2e</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, f1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // f1 = 3.14e+00</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2lf</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d2 = 314.00</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2e</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d2 = 3.14e+02</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br></div></div><h3 id="_1-3-3-字面量后缀" tabindex="-1">1.3.3 字面量后缀 <a class="header-anchor" href="#_1-3-3-字面量后缀" aria-label="Permalink to &quot;1.3.3 字面量后缀&quot;">​</a></h3><ul><li><p>浮点数字面量默认是 double 类型。</p></li><li><p>如果需要表示 float 类型的字面量，需要后面添加后缀 f 或 F。</p></li><li><p>如果需要表示 long double 类型的字面量，需要后面添加后缀 l 或 L。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> float</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> f1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3.1415926</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">f</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3.1415926</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3.1415926</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">L</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;f1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2f</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, f1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // f1 = 3.14</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.3lf</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d2 = 3.142</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.4Lf</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d3 = 3.1416</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br></div></div><h3 id="_1-3-4-类型占用的内存大小-存储空间" tabindex="-1">1.3.4 类型占用的内存大小（存储空间） <a class="header-anchor" href="#_1-3-4-类型占用的内存大小-存储空间" aria-label="Permalink to &quot;1.3.4 类型占用的内存大小（存储空间）&quot;">​</a></h3><ul><li><p>可以通过 sizeof 运算符来获取 float、double 以及 long double 类型占用的内存大小（存储空间）。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;float 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">float</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">));</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;double 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">));</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 8</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;long double 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">));</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 16</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><h3 id="_1-3-5-类型的取值范围" tabindex="-1">1.3.5 类型的取值范围 <a class="header-anchor" href="#_1-3-5-类型的取值范围" aria-label="Permalink to &quot;1.3.5 类型的取值范围&quot;">​</a></h3><ul><li><p>可以通过 <code>#include &lt;float.h&gt;</code> 来获取类型的取值范围。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;float.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;float 的取值范围是：[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.38f</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%f</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">] </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, FLT_MIN, FLT_MAX);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;double 的取值范围是：[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lf</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lf</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">] </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, DBL_MIN, DBL_MAX);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;double 的取值范围是：[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%Lf</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%Lf</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">] </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, LDBL_MIN, LDBL_MAX);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><h2 id="_1-4-字符类型" tabindex="-1">1.4 字符类型 <a class="header-anchor" href="#_1-4-字符类型" aria-label="Permalink to &quot;1.4 字符类型&quot;">​</a></h2><h3 id="_1-4-1-概述" tabindex="-1">1.4.1 概述 <a class="header-anchor" href="#_1-4-1-概述" aria-label="Permalink to &quot;1.4.1 概述&quot;">​</a></h3><ul><li>在生活中，我们会经常说：今天天气真 <code>好</code>，我的性别是 <code>女</code>，我今年 <code>10</code> 岁，像这类数据，在 C 语言中就可以用字符（char）来表示。</li><li>在 C 语言中，变量的<code>字符类型</code>可以表示<code>单</code>个字符，如：<code>&#39;1&#39;</code>、<code>&#39;A&#39;</code>、<code>&#39;&amp;&#39;</code>。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>C 语言的出现在 1972 年，由美国人丹尼斯·里奇设计出来；那个时候，只需要 1 个字节的内存空间，就可以完美的表示拉丁体系（英文）文字，如：a-z、A-Z、0-9 以及一些特殊符号；所以，C 语言中不支持多个字节的字符，如：中文、日文等。</li><li>C 语言中没有字符串类型，是使用字符数组（char 数组）来模拟字符串的，并且字符数组也不是字符串，而是构造类型。</li><li>在 C 语言中，如果想要输出中文、日文等多字节字符，就需要使用字符数组（char 数组）。</li><li>在 C++、Java 等高级编程语言中，已经提供了 String （字符串）类型，原生支持 Unicode，可以方便地处理多语言和特殊字符。</li></ul></div><ul><li>在 C 语言中，可以使用<code>转义字符 \\</code>来表示特殊含义的字符。</li></ul><table tabindex="0"><thead><tr><th><strong>转义字符</strong></th><th><strong>说明</strong></th></tr></thead><tbody><tr><td><code>\\b</code></td><td>退格</td></tr><tr><td><code>\\n</code></td><td>换行符</td></tr><tr><td><code>\\r</code></td><td>回车符</td></tr><tr><td><code>\\t</code></td><td>制表符</td></tr><tr><td><code>\\&quot;</code></td><td>双引号</td></tr><tr><td><code>\\&#39;</code></td><td>单引号</td></tr><tr><td><code>\\\\</code></td><td>反斜杠</td></tr><tr><td>...</td><td></td></tr></tbody></table><h3 id="_1-4-2-格式占位符" tabindex="-1">1.4.2 格式占位符 <a class="header-anchor" href="#_1-4-2-格式占位符" aria-label="Permalink to &quot;1.4.2 格式占位符&quot;">​</a></h3><ul><li><p>在 C 语言中，使用 <code>%c</code> 来表示 char 类型。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;&amp;&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;c = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, c);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // c = &amp;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;a&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;c2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, c2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // c2 = a</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;A&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;c3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, c3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // c3 = A</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br></div></div><h3 id="_1-4-3-类型占用的内存大小-存储空间" tabindex="-1">1.4.3 类型占用的内存大小（存储空间） <a class="header-anchor" href="#_1-4-3-类型占用的内存大小-存储空间" aria-label="Permalink to &quot;1.4.3 类型占用的内存大小（存储空间）&quot;">​</a></h3><ul><li><p>可以通过 sizeof 运算符来获取 char 类型占用的内存大小（存储空间）。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;char 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">));</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 1 </span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned char 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">));</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 1</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br></div></div><h3 id="_1-4-4-类型的取值范围" tabindex="-1">1.4.4 类型的取值范围 <a class="header-anchor" href="#_1-4-4-类型的取值范围" aria-label="Permalink to &quot;1.4.4 类型的取值范围&quot;">​</a></h3><ul><li><p>可以通过 <code>#include &lt;limits.h&gt;</code> 来获取类型的取值范围。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;char 范围是[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">] </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, CHAR_MIN,CHAR_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [-128,127]</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned char 范围是[0,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, UCHAR_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [0,255]</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><h3 id="_1-4-3-字符类型的本质" tabindex="-1">1.4.3 字符类型的本质 <a class="header-anchor" href="#_1-4-3-字符类型的本质" aria-label="Permalink to &quot;1.4.3 字符类型的本质&quot;">​</a></h3><ul><li>在 C 语言中，char 本质上就是一个整数，是 ASCII 码中对应的数字，占用的内存大小是 1 个字节（存储空间），所以 char 类型也可以进行数学运算。</li></ul><p><img src="`+E+'" alt=""></p><ul><li>char 类型同样分为 signed char（无符号）和 unsigned char（有符号），其中 signed char 取值范围-128 ~ 127，unsigned char取值范围 0 ~ 255，默认是否带符号取决于当前运行环境。</li><li><code>字符类型的数据</code>在计算机中<code>存储</code>和<code>读取</code>的过程，如下所示：</li></ul><p><img src="'+c+`" alt=""></p><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // char 类型字面量需要使用单引号包裹</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;A&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;9&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\t</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;c1=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, c3=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, c2=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a1, a3, a2);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // char 类型本质上整数可以进行运算</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;b&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 101</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">-&gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, b1, b1);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">-&gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, b2, b2);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">+</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, b1, b2, b1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b2);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // char 类型取值范围</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 200</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 无符号 char 取值范围 0 ~255</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 200</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 有符号 char 取值范围 -128~127，c2会超出范围</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 200</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 当前系统，char 默认是 signed char</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;c1=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, c2=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, c3=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, c1, c2, c3);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br></div></div><h2 id="_1-5-布尔类型" tabindex="-1">1.5 布尔类型 <a class="header-anchor" href="#_1-5-布尔类型" aria-label="Permalink to &quot;1.5 布尔类型&quot;">​</a></h2><h3 id="_1-5-1-概述" tabindex="-1">1.5.1 概述 <a class="header-anchor" href="#_1-5-1-概述" aria-label="Permalink to &quot;1.5.1 概述&quot;">​</a></h3><ul><li>布尔值用于表示 true（真）、false（假）两种状态，通常用于逻辑运算和条件判断。</li></ul><h3 id="_1-5-2-早期的布尔类型" tabindex="-1">1.5.2 早期的布尔类型 <a class="header-anchor" href="#_1-5-2-早期的布尔类型" aria-label="Permalink to &quot;1.5.2 早期的布尔类型&quot;">​</a></h3><ul><li><p>在 C 语言标准（C89）中，并没有为布尔值单独设置一个数据类型，所以在判断真、假的时候，使用 <code>0</code> 表示 <code>false</code>（假），<code>非 0</code> 表示 <code>true</code>（真）。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> </span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 使用整型来表示真和假两种状态</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> handsome </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">; </span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;帅不帅[0 丑，1 帅]： &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">handsome);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (handsome) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很帅！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很丑！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h3 id="_1-5-3-宏定义的布尔类型" tabindex="-1">1.5.3 宏定义的布尔类型 <a class="header-anchor" href="#_1-5-3-宏定义的布尔类型" aria-label="Permalink to &quot;1.5.3 宏定义的布尔类型&quot;">​</a></h3><ul><li><p>判断真假的时候，以 <code>0</code> 为 <code>false</code>（假）、<code>1</code> 为 <code>true</code>（真），并不直观；所以，我们可以借助 C 语言的宏定义。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">// 宏定义</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#define</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> BOOL</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#define</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> TRUE</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#define</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> FALSE</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> BOOL handsome </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;帅不帅[FALSE 丑，TRUE 帅]： &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">handsome);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (handsome) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很帅！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很丑！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br></div></div><h3 id="_1-5-4-c99-标准中的布尔类型" tabindex="-1">1.5.4 C99 标准中的布尔类型 <a class="header-anchor" href="#_1-5-4-c99-标准中的布尔类型" aria-label="Permalink to &quot;1.5.4 C99 标准中的布尔类型&quot;">​</a></h3><ul><li><p>在 C99 中提供了 <code>_Bool</code> 关键字，用于表示布尔类型；其实，<code>_Bool</code>类型的值是整数类型的别名，和一般整型不同的是，<code>_Bool</code>类型的值只能赋值为 <code>0</code> 或 <code>1</code> （0 表示假、1 表示真），其它<code>非 0</code> 的值都会被存储为 <code>1</code> 。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> _Bool</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> handsome </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;帅不帅[0 丑，1 帅]： &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">handsome);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (handsome) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很帅！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很丑！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h3 id="_1-5-5-c99-标准头文件中的布尔类型-推荐" tabindex="-1">1.5.5 C99 标准头文件中的布尔类型（推荐） <a class="header-anchor" href="#_1-5-5-c99-标准头文件中的布尔类型-推荐" aria-label="Permalink to &quot;1.5.5 C99 标准头文件中的布尔类型（推荐）&quot;">​</a></h3><ul><li>在 C99 中提供了一个头文件 <code>&lt;stdbool.h&gt;</code>，定义了 <code>bool</code> 代表 <code>_Bool</code>，<code>false</code> 代表 <code>0</code> ，<code>true</code> 代表 <code>1</code> 。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>在 C++、Java 等高级编程语言中是有 boolean 类型的关键字的。</p></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> bool</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> handsome </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> false</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;帅不帅[false 丑，true 帅]： &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">handsome);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (handsome) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很帅！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很丑！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h2 id="_1-6-数据类型转换" tabindex="-1">1.6 数据类型转换 <a class="header-anchor" href="#_1-6-数据类型转换" aria-label="Permalink to &quot;1.6 数据类型转换&quot;">​</a></h2><h3 id="_1-6-1-概述" tabindex="-1">1.6.1 概述 <a class="header-anchor" href="#_1-6-1-概述" aria-label="Permalink to &quot;1.6.1 概述&quot;">​</a></h3><ul><li>在 C 语言编程中，经常需要对不同类型的数据进行运算，运算前需要先转换为同一类型，再运算。为了解决数据类型不一致的问题，需要对数据的类型进行转换。</li></ul><h3 id="_1-6-2-自动类型转换-隐式转换" tabindex="-1">1.6.2 自动类型转换（隐式转换） <a class="header-anchor" href="#_1-6-2-自动类型转换-隐式转换" aria-label="Permalink to &quot;1.6.2 自动类型转换（隐式转换）&quot;">​</a></h3><h4 id="_1-6-2-1-运算过程中的自动类型转换" tabindex="-1">1.6.2.1 运算过程中的自动类型转换 <a class="header-anchor" href="#_1-6-2-1-运算过程中的自动类型转换" aria-label="Permalink to &quot;1.6.2.1 运算过程中的自动类型转换&quot;">​</a></h4><ul><li>不同类型的数据进行混合运算的时候，会发生数据类型转换，<code>窄类型会自动转换为宽类型</code>，这样就不会造成精度损失。</li></ul><p><img src="`+g+'" alt=""></p><ul><li>转换规则： <ul><li>① 不同类型的整数进行运算的时候，窄类型整数会自动转换为宽类型整数。</li><li>② 不同类型的浮点数进行运算的时候，精度小的类型会自动转换为精度大的类型。</li><li>③ 整数和浮点数进行运算的时候，整数会自动转换为浮点数。</li></ul></li><li>转换方向：</li></ul><p><img src="'+F+`" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>最好避免无符号整数与有符号整数的混合运算，因为这时 C 语言会自动将 signed int 转为 unsigned int ，可能不会得到预期的结果。</p></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">/**</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> * 不同的整数类型混合运算时，宽度较小的类型会提升为宽度较大的类型，比如 short 转为 int ，int 转为 long 等。</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> */</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 20</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // s1 是 short 类型，i 是 int 类型，当 s1 和 i 运算的时候，会自动转为 int 类型后，然后再计算。</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> result </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;result = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, result);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 20</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // n2 是有符号，n3 是无符号，当 n2 和 n3 运算的时候，会自动转为无符号类型后，然后再计算。</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> result </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n3;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;result = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, result);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">/**</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">* 不同的浮点数类型混合运算时，宽度较小的类型转为宽度较大的类型，比如 float 转为 double ，double 转为 long double 。</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">*/</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> float</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> f1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1.25</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">f</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 4.58667435</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // f1 是 float 类型，d2 是 double 类型，当 f1 和 d2 运算的时候，会自动转为 double 类型后，然后再计算。</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> result </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> f1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d2;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;result = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.8lf</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, result);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">/**</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> * 整型与浮点型运算，整型转为浮点型</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> */</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n4 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1.67</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // n4 是 int 类型，d3 是 double 类型，当 n4 和 d3 运算的时候，会自动转为 double 类型后，然后再计算。</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> result </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n4 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d3;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2lf</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, result);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h4 id="_1-6-2-2-赋值时的自动类型转换" tabindex="-1">1.6.2.2 赋值时的自动类型转换 <a class="header-anchor" href="#_1-6-2-2-赋值时的自动类型转换" aria-label="Permalink to &quot;1.6.2.2 赋值时的自动类型转换&quot;">​</a></h4><ul><li>在赋值运算中，赋值号两边量的数据类型不同时，等号右边的类型将转换为左边的类型。</li><li>如果窄类型赋值给宽类型，不会造成精度损失；如果宽类型赋值给窄类型，会造成精度损失。</li></ul><p><img src="`+y+`" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>C 语言在检查类型匹配方面不太严格，最好不要养成这样的习惯。</p></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 赋值：窄类型赋值给宽类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a1;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a2: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2f\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a2: 10.00</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 转换：将宽类型转换为窄类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10.5</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b1;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;b2: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, b2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // b2: 10</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br></div></div><h3 id="_1-6-3-强制类型转换" tabindex="-1">1.6.3 强制类型转换 <a class="header-anchor" href="#_1-6-3-强制类型转换" aria-label="Permalink to &quot;1.6.3 强制类型转换&quot;">​</a></h3><ul><li>隐式类型转换中的宽类型赋值给窄类型，编译器是会产生警告的，提示程序存在潜在的隐患，如果非常明确地希望转换数据类型，就需要用到强制（或显式）类型转换。</li><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">数据类型 变量名 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (类型名)变量、常量或表达式;</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>强制类型转换会导致精度损失！！！</p></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(){</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1.934</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 4.2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)d1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)d2;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1 转为 1，d2 转为 4，结果是 5</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)(d1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1+d2 = 6.134，6.134 转为 6</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">3.5</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> *</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> +</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 6</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> *</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1.5</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 35.0 + 9.0 = 44.0 -&gt; int = 44</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num1=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num1);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num2=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num2);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num3=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num3);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><h1 id="第二章-运算符-⭐" tabindex="-1">第二章：运算符（⭐） <a class="header-anchor" href="#第二章-运算符-⭐" aria-label="Permalink to &quot;第二章：运算符（⭐）&quot;">​</a></h1><h2 id="_2-1-概述" tabindex="-1">2.1 概述 <a class="header-anchor" href="#_2-1-概述" aria-label="Permalink to &quot;2.1 概述&quot;">​</a></h2><ul><li>运算符是一种特殊的符号，用于数据的运算、赋值和比较等。</li><li><code>表达式</code>指的是一组运算数、运算符的组合，表达式<code>一定具有值</code>，一个变量或一个常量可以是表达式，变量、常量和运算符也可以组成表达式，如：</li></ul><p><img src="`+u+'" alt=""></p><ul><li><code>操作数</code>指的是<code>参与运算</code>的<code>值</code>或者<code>对象</code>，如：</li></ul><p><img src="'+b+`" alt=""></p><ul><li>根据<code>操作数</code>的<code>个数</code>，可以将运算符分为： <ul><li>一元运算符（一目运算符）。</li><li>二元运算符（二目运算符）。</li><li>三元运算符（三目运算符）。</li></ul></li><li>根据<code>功能</code>，可以将运算符分为： <ul><li>算术运算符。</li><li>关系运算符（比较运算符）。</li><li>逻辑运算符。</li><li>赋值运算符。</li><li>逻辑运算符。</li><li>位运算符。</li><li>三元运算符。</li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>掌握一个运算符，需要关注以下几个方面：</p><ul><li>① 运算符的含义。</li><li>② 运算符操作数的个数。</li><li>③ 运算符所组成的表达式。</li><li>④ 运算符有无副作用，即：运算后是否会修改操作数的值。</li></ul></div><h2 id="_2-2-算术运算符" tabindex="-1">2.2 算术运算符 <a class="header-anchor" href="#_2-2-算术运算符" aria-label="Permalink to &quot;2.2 算术运算符&quot;">​</a></h2><ul><li>算术运算符是对数值类型的变量进行运算的，如下所示：</li></ul><table tabindex="0"><thead><tr><th>运算符</th><th>描述</th><th>操作数个数</th><th>组成的表达式的值</th><th>副作用</th></tr></thead><tbody><tr><td><code>+</code></td><td>正号</td><td>1</td><td>操作数本身</td><td>❎</td></tr><tr><td><code>-</code></td><td>负号</td><td>1</td><td>操作数符号取反</td><td>❎</td></tr><tr><td><code>+</code></td><td>加号</td><td>2</td><td>两个操作数之和</td><td>❎</td></tr><tr><td><code>-</code></td><td>减号</td><td>2</td><td>两个操作数之差</td><td>❎</td></tr><tr><td><code>*</code></td><td>乘号</td><td>2</td><td>两个操作数之积</td><td>❎</td></tr><tr><td><code>/</code></td><td>除号</td><td>2</td><td>两个操作数之商</td><td>❎</td></tr><tr><td><code>%</code></td><td>取模（取余）</td><td>2</td><td>两个操作数相除的余数</td><td>❎</td></tr><tr><td><code>++</code></td><td>自增</td><td>1</td><td>操作数自增前或自增后的值</td><td>✅</td></tr><tr><td><code>--</code></td><td>自减</td><td>1</td><td>操作数自减前或自减后的值</td><td>✅</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>自增和自减：</p><ul><li>① 自增、自减运算符可以写在操作数的前面也可以写在操作数后面，不论前面还是后面，对操作数的副作用是一致的。</li><li>② 自增、自减运算符在前在后，对于表达式的值是不同的。 如果运算符在前，表达式的值是操作数自增、自减之后的值；如果运算符在后，表达式的值是操作数自增、自减之前的值。</li><li>③ <code>变量前++</code>：变量先自增 1 ，然后再运算；<code>变量后++</code>：变量先运算，然后再自增 1 。</li><li>④ <code>变量前--</code>：变量先自减 1 ，然后再运算；<code>变量后--</code>：变量先运算，然后再自减 1 。</li></ul></div><ul><li>示例：正号和负号</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 12</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">x, x2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> +</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">x;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> y </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">67</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> y1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">y, y2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> +</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">y;</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;x1=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, x2=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, x1, x2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // x1=-12, x2=12</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;y1=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, y2=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, y1, y2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // y1=67, y2=-67</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：加、减、乘、除（整数之间做除法时，结果只保留整数部分而舍弃小数部分）、取模</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 5</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> + </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 5 + 2 = 7</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> - </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">-</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 5 - 2 = 3</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> × </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">*</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 5 × 2 = 10</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> / </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">/</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 5 / 2 = 2</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> %%</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> %d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">%</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 5 % 2 = 1</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：取模（运算结果的符号与被模数也就是第一个操作数相同。）</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> %</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;10 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%%</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, res1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 10 % 3 = 1</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> %</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;-10 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%%</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, res2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // -10 % 3 = -1</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> %</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;10 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%%</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> -3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, res3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 10 % -3 = 1</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res4 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> %</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;-10 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%%</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> -3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, res4);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // -10 % -3 = -1</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br></div></div><ul><li>示例：自增和自减</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 20</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i1</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">++</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i = 10</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i1 = 11</span></span>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> ++</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">i1;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i = 12</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i1 = 12</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i2</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">--</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i = 20</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i2 = 19</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> --</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">i2;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i = 18</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i2 = 18</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">/*</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 随意给出一个整数，打印显示它的个位数，十位数，百位数的值。</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 格式如下：</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 数字xxx的情况如下：</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 个位数：</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 十位数：</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 百位数：</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 例如：</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 数字153的情况如下：</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 个位数：3</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 十位数：5</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 百位数：1</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> */</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 153</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> bai </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">/</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> shi </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">%</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> /</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ge </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">%</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;百位为：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, bai);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;十位为：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, shi);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;个位为：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ge);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br></div></div><h2 id="_2-3-关系运算符-比较运算符" tabindex="-1">2.3 关系运算符（比较运算符） <a class="header-anchor" href="#_2-3-关系运算符-比较运算符" aria-label="Permalink to &quot;2.3 关系运算符（比较运算符）&quot;">​</a></h2><ul><li>常见的关系运算符，如下所示：</li></ul><table tabindex="0"><thead><tr><th>运算符</th><th>描述</th><th>操作数个数</th><th>组成的表达式的值</th><th>副作用</th></tr></thead><tbody><tr><td><code>==</code></td><td>相等</td><td>2</td><td>0 或 1</td><td>❎</td></tr><tr><td><code>!=</code></td><td>不相等</td><td>2</td><td>0 或 1</td><td>❎</td></tr><tr><td><code>&lt;</code></td><td>小于</td><td>2</td><td>0 或 1</td><td>❎</td></tr><tr><td><code>&gt;</code></td><td>大于</td><td>2</td><td>0 或 1</td><td>❎</td></tr><tr><td><code>&lt;=</code></td><td>小于等于</td><td>2</td><td>0 或 1</td><td>❎</td></tr><tr><td><code>&gt;=</code></td><td>大于等于</td><td>2</td><td>0 或 1</td><td>❎</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① C 语言中，没有严格意义上的布尔类型，所以可以 0（假） 或 1（真）表示布尔类型的值。</li><li>② 不要将 <code>==</code> 写成 <code>=</code>，<code>==</code> 是比较运算符，而 <code>=</code> 是赋值运算符。</li><li>③ <code>&gt;=</code> 或 <code>&lt;=</code>含义是只需要满足 <code>大于或等于</code>、<code>小于或等于</code>其中一个条件，结果就返回真。</li></ul></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 8</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 7</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a &gt; b 的结果是：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a &gt; b 的结果是：1</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a &gt;= b 的结果是：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a &gt;= b 的结果是：1</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a &lt; b 的结果是：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a &lt; b 的结果是：0</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a &lt;= b 的结果是：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a &lt;= b 的结果是：0</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a == b 的结果是：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">==</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a == b 的结果是：0</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a != b 的结果是：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">!=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a != b 的结果是：1</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br></div></div><h2 id="_2-4-逻辑运算符" tabindex="-1">2.4 逻辑运算符 <a class="header-anchor" href="#_2-4-逻辑运算符" aria-label="Permalink to &quot;2.4 逻辑运算符&quot;">​</a></h2><ul><li>常见的逻辑运算符，如下所示：</li></ul><table tabindex="0"><thead><tr><th>运算符</th><th>描述</th><th>操作数个数</th><th>组成的表达式的值</th><th>副作用</th></tr></thead><tbody><tr><td><code>&amp;&amp;</code></td><td>逻辑与</td><td>2</td><td>0 或 1</td><td>❎</td></tr><tr><td>\`</td><td></td><td>\`</td><td>逻辑或</td><td>2</td></tr><tr><td><code>!</code></td><td>逻辑非</td><td>2</td><td>0 或 1</td><td>❎</td></tr></tbody></table><ul><li>逻辑运算符提供逻辑判断功能，用于构建更复杂的表达式，如下所示：</li></ul><table tabindex="0"><thead><tr><th>a</th><th>b</th><th>a &amp;&amp; b</th><th>a || b</th><th>!a</th></tr></thead><tbody><tr><td>1（真）</td><td>1（真）</td><td>1（真）</td><td>1（真）</td><td>0（假）</td></tr><tr><td>1（真）</td><td>0（假）</td><td>0（假）</td><td>1（真）</td><td>0（假）</td></tr><tr><td>0（假）</td><td>1（真）</td><td>0（假）</td><td>1（真）</td><td>1（真）</td></tr><tr><td>0（假）</td><td>0（假）</td><td>0（假）</td><td>0（假）</td><td>1（真）</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 对于逻辑运算符来说，任何非零值都表示真，零值表示假，如：<code>5 || 0</code> 返回 <code>1</code> ，<code>5 &amp;&amp; 0</code> 返回 <code>0</code> 。</li><li>② 短路现象： <ul><li>对于 <code>a &amp;&amp; b</code> 操作来说，当 a 为假(或 0 )时，因为 <code>a &amp;&amp; b</code> 结果必定为 0，所以不再执行表达式 b。</li><li>对于 <code>a || b</code> 操作来说，当 a 为真(或非 0 )时，因为 <code>a || b</code> 结果必定为 1，所以不再执行表达式 b。</li></ul></li></ul></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入整数a的值：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">a);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入整数b的值：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">b);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &gt; </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt; </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">// 短路现象</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> j </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> j</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">++</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> &gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;床前明月光</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 这行代码不会执行</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;我叫郭德纲</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, j);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> //10</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">// 短路现象</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> j </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">||</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> j</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">++</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> &gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;床前明月光 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;我叫郭德纲 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 这行代码不会被执行</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, j);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> //10</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h2 id="_2-5-赋值运算符" tabindex="-1">2.5 赋值运算符 <a class="header-anchor" href="#_2-5-赋值运算符" aria-label="Permalink to &quot;2.5 赋值运算符&quot;">​</a></h2><ul><li>常见的赋值运算符，如下所示：</li></ul><table tabindex="0"><thead><tr><th>运算符</th><th>描述</th><th>操作数个数</th><th>组成的表达式的值</th><th>副作用</th></tr></thead><tbody><tr><td><code>==</code></td><td>赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>+=</code></td><td>相加赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>-=</code></td><td>相减赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>*=</code></td><td>相乘赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>/=</code></td><td>相除赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>%=</code></td><td>取余赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>&lt;&lt;=</code></td><td>左移赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>&gt;&gt;=</code></td><td>右移赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>&amp;=</code></td><td>按位与赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>^=</code></td><td>按位异或赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td>\`</td><td>=\`</td><td>按位或赋值</td><td>2</td><td>左边操作数的值</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 赋值运算符的第一个操作数（左值）必须是变量的形式，第二个操作数可以是任何形式的表达式。</li><li>② 赋值运算符的副作用针对第一个操作数。</li></ul></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a = a + 3</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a = 6</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">-=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // b = b - 3</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;b = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // b = 0</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">*=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // c = c * 3</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;c = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, c);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // c = 9</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">/=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d = d / 3</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d = 1</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> e </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> e </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">%=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // e = e % 3</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;e = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, e);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // e = 0</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br></div></div><h2 id="_2-6-位运算符-了解" tabindex="-1">2.6 位运算符（了解） <a class="header-anchor" href="#_2-6-位运算符-了解" aria-label="Permalink to &quot;2.6 位运算符（了解）&quot;">​</a></h2><h3 id="_2-6-1-概述" tabindex="-1">2.6.1 概述 <a class="header-anchor" href="#_2-6-1-概述" aria-label="Permalink to &quot;2.6.1 概述&quot;">​</a></h3><ul><li>C 语言提供了一些位运算符，能够让我们操作二进制位（bit）。</li><li>常见的位运算符，如下所示。</li></ul><table tabindex="0"><thead><tr><th>运算符</th><th>描述</th><th>操作数个数</th><th>运算规则</th><th>副作用</th></tr></thead><tbody><tr><td><code>&amp;</code></td><td>按位与</td><td>2</td><td>两个二进制位都为 1 ，结果为 1 ，否则为 0 。</td><td>❎</td></tr><tr><td>\`</td><td>\`</td><td>按位或</td><td>2</td><td>两个二进制位只要有一个为 1（包含两个都为 1 的情况），结果为 1 ，否则为 0 。</td></tr><tr><td><code>^</code></td><td>按位异或</td><td>2</td><td>两个二进制位一个为 0 ，一个为 1 ，结果为 1，否则为 0 。</td><td>❎</td></tr><tr><td><code>~</code></td><td>按位取反</td><td>2</td><td>将每一个二进制位变成相反值，即 0 变成 1 ， 1 变 成 0 。</td><td>❎</td></tr><tr><td><code>&lt;&lt;</code></td><td>二进制左移</td><td>2</td><td>将一个数的各二进制位全部左移指定的位数，左 边的二进制位丢弃，右边补 0。</td><td>❎</td></tr><tr><td><code>&gt;&gt;</code></td><td>二进制右移</td><td>2</td><td>将一个数的各二进制位全部右移指定的位数，正数左补 0，负数左补 1，右边丢弃。</td><td>❎</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>操作数在进行位运算的时候，以它的补码形式计算！！！</p></div><h3 id="_2-6-2-输出二进制位" tabindex="-1">2.6.2 输出二进制位 <a class="header-anchor" href="#_2-6-2-输出二进制位" aria-label="Permalink to &quot;2.6.2 输出二进制位&quot;">​</a></h3><ul><li><p>在 C 语言中，<code>printf</code> 是没有提供输出二进制位的格式占位符的；但是，我们可以手动实现，以方便后期操作。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">/**</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> * 获取指定整数的二进制表示</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> * </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">@param</span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;"> num</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 整数</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> * </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">@return</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 二进制表示的字符串，不包括前导的 &#39;0b&#39; 字符</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> */</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">char*</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> getBinary</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;"> num</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> static</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;"> binaryString</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">33</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">];</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i, j;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(num) </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">*</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 8</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, j </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">; i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">; i</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">--</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, j</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">++</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> const</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> bit </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;&gt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i) </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;"> binaryString</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">[j] </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> bit </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;0&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;"> binaryString</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">[j] </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\0</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> binaryString;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 17</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">12</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;整数 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 的二进制表示：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%s</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">getBinary</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(a));</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;整数 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 的二进制表示：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%s</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, b, </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">getBinary</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(b));</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br></div></div><h3 id="_2-6-3-按位与" tabindex="-1">2.6.3 按位与 <a class="header-anchor" href="#_2-6-3-按位与" aria-label="Permalink to &quot;2.6.3 按位与&quot;">​</a></h3><ul><li><p>按位与 <code>&amp;</code> 的运算规则是：如果二进制对应的位上都是 1 才是 1 ，否则为 0 ，即：</p><ul><li><code>1 &amp; 1</code> 的结果是 <code>1</code> 。</li><li><code>1 &amp; 0</code> 的结果是 <code>0</code> 。</li><li><code>0 &amp; 1</code> 的结果是 <code>0</code> 。</li><li><code>0 &amp; 0</code> 的结果是 <code>0</code> 。</li></ul></li><li><p>示例：<code>9 &amp; 7 = 1</code></p></li></ul><p><img src="`+o+'" alt=""></p><ul><li>示例：<code>-9 &amp; 7 = 7</code></li></ul><p><img src="'+C+'" alt=""></p><h3 id="_2-6-4-按位或" tabindex="-1">2.6.4 按位或 <a class="header-anchor" href="#_2-6-4-按位或" aria-label="Permalink to &quot;2.6.4 按位或&quot;">​</a></h3><ul><li><p>按位与 <code>|</code> 的运算规则是：如果二进制对应的位上只要有 1 就是 1 ，否则为 0 ，即：</p><ul><li><code>1 | 1</code> 的结果是 <code>1</code> 。</li><li><code>1 | 0</code> 的结果是 <code>1</code> 。</li><li><code>0 | 1</code> 的结果是 <code>1</code> 。</li><li><code>0 | 0</code> 的结果是 <code>0</code> 。</li></ul></li><li><p>示例：<code>9 | 7 = 15</code></p></li></ul><p><img src="'+m+'" alt=""></p><ul><li>示例：<code>-9 | 7 = -9</code></li></ul><p><img src="'+B+'" alt=""></p><h3 id="_2-6-5-按位异或" tabindex="-1">2.6.5 按位异或 <a class="header-anchor" href="#_2-6-5-按位异或" aria-label="Permalink to &quot;2.6.5 按位异或&quot;">​</a></h3><ul><li>按位与 <code>^</code> 的运算规则是：如果二进制对应的位上一个为 1 一个为 0 就为 1 ，否则为 0 ，即： <ul><li><code>1 ^ 1</code> 的结果是 <code>0</code> 。</li><li><code>1 ^ 0</code> 的结果是 <code>1</code> 。</li><li><code>0 ^ 1</code> 的结果是 <code>1</code> 。</li><li><code>0 ^ 0</code> 的结果是 <code>0</code> 。</li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>按位异或的场景有：</p><ul><li>① 交换两个数值：异或操作可以在不使用临时变量的情况下交换两个变量的值。</li><li>② 加密或解密：异或操作用于简单的加密和解密算法。</li><li>③ 错误检测和校正：异或操作可以用于奇偶校验位的计算和检测错误（RAID-3 以及以上）。</li><li>……</li></ul></div><ul><li>示例：<code>9 ^ 7 = 14</code></li></ul><p><img src="'+A+'" alt=""></p><ul><li>示例：<code>-9 ^ 7 = -16</code></li></ul><p><img src="'+D+'" alt=""></p><h3 id="_2-6-6-按位取反" tabindex="-1">2.6.6 按位取反 <a class="header-anchor" href="#_2-6-6-按位取反" aria-label="Permalink to &quot;2.6.6 按位取反&quot;">​</a></h3><ul><li><p>运算规则：如果二进制对应的位上是 1，则结果为0；如果是 0 ，则结果为 1 。</p><ul><li><code>~0</code> 的结果是 <code>1</code> 。</li><li><code>~1</code> 的结果是 <code>0</code> 。</li></ul></li><li><p>示例：<code>~9 = -10</code></p></li></ul><p><img src="'+v+'" alt=""></p><ul><li>示例：<code>~-9 = 8</code></li></ul><p><img src="'+q+'" alt=""></p><h3 id="_2-6-7-二进制左移" tabindex="-1">2.6.7 二进制左移 <a class="header-anchor" href="#_2-6-7-二进制左移" aria-label="Permalink to &quot;2.6.7 二进制左移&quot;">​</a></h3><ul><li><p>在一定范围内，数据每向左移动一位，相当于原数据 * 2。（正数、负数都适用）</p></li><li><p>示例：<code>3 &lt;&lt; 4 = 48</code> （3 × 2^4）</p></li></ul><p><img src="'+f+'" alt=""></p><ul><li>示例：<code>-3 &lt;&lt; 4 = -48</code> （-3 × 2 ^4）</li></ul><p><img src="'+_+'" alt=""></p><h3 id="_2-6-7-二进制右移" tabindex="-1">2.6.7 二进制右移 <a class="header-anchor" href="#_2-6-7-二进制右移" aria-label="Permalink to &quot;2.6.7 二进制右移&quot;">​</a></h3><ul><li>在一定范围内，数据每向右移动一位，相当于原数据 / 2。（正数、负数都适用）</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 如果不能整除，则向下取整。</li><li>② 右移运算符最好只用于无符号整数，不要用于负数。因为不同系统对于右移后如何处理负数的符号位，有不同的做法，可能会得到不一样的结果。</li></ul></div><ul><li>示例：<code>69 &gt;&gt; 4 = 4</code> （69 / 2^4 ）</li></ul><p><img src="'+x+'" alt=""></p><ul><li>示例：<code>-69 &gt;&gt; 4 = -5</code> （-69 / 2^4 ）</li></ul><p><img src="'+z+`" alt=""></p><h2 id="_2-7-三元运算符" tabindex="-1">2.7 三元运算符 <a class="header-anchor" href="#_2-7-三元运算符" aria-label="Permalink to &quot;2.7 三元运算符&quot;">​</a></h2><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">条件表达式 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">?</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 表达式1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">:</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 表达式2 ;</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>如果条件表达式为非 0 （真），则整个表达式的值是表达式 1 。</li><li>如果条件表达式为 0 （假），则整个表达式的值是表达式 2 。</li></ul></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> m </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 110</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 20</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> result </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> m </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">?</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> m </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">:</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;result = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, result);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // result = 110</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><h2 id="_2-8-运算符优先级" tabindex="-1">2.8 运算符优先级 <a class="header-anchor" href="#_2-8-运算符优先级" aria-label="Permalink to &quot;2.8 运算符优先级&quot;">​</a></h2><ul><li>C 语言中运算符的优先级，如下所示：</li></ul><table tabindex="0"><thead><tr><th><strong>优先级</strong></th><th><strong>运算符</strong></th><th><strong>名称或含义</strong></th><th><strong>结合方向</strong></th></tr></thead><tbody><tr><td><strong>1</strong></td><td><code>[]</code></td><td>数组下标</td><td>左到右</td></tr><tr><td></td><td><code>()</code></td><td>圆括号</td><td></td></tr><tr><td></td><td><code>.</code></td><td>成员选择（对象）</td><td></td></tr><tr><td></td><td><code>-&gt;</code></td><td>成员选择（指针）</td><td></td></tr><tr><td><strong>2</strong></td><td><code>-</code></td><td>负号运算符</td><td>右到左</td></tr><tr><td></td><td><code>（类型）</code></td><td>强制类型转换</td><td></td></tr><tr><td></td><td><code>++</code></td><td>自增运算符</td><td></td></tr><tr><td></td><td><code>--</code></td><td>自减运算符</td><td></td></tr><tr><td></td><td><code>*</code></td><td>取值运算符</td><td></td></tr><tr><td></td><td><code>&amp;</code></td><td>取地址运算符</td><td></td></tr><tr><td></td><td><code>!</code></td><td>逻辑非运算符</td><td></td></tr><tr><td></td><td><code>~</code></td><td>按位取反运算符</td><td></td></tr><tr><td></td><td><code>sizeof</code></td><td>长度运算符</td><td></td></tr><tr><td><strong>3</strong></td><td><code>/</code></td><td>除</td><td>左到右</td></tr><tr><td></td><td><code>*</code></td><td>乘</td><td></td></tr><tr><td></td><td><code>%</code></td><td>余数（取模）</td><td></td></tr><tr><td><strong>4</strong></td><td><code>+</code></td><td>加</td><td>左到右</td></tr><tr><td></td><td><code>-</code></td><td>减</td><td></td></tr><tr><td><strong>5</strong></td><td><code>&lt;&lt;</code></td><td>左移</td><td>左到右</td></tr><tr><td></td><td><code>&gt;&gt;</code></td><td>右移</td><td></td></tr><tr><td><strong>6</strong></td><td><code>&gt;</code></td><td>大于</td><td>左到右</td></tr><tr><td></td><td><code>&gt;=</code></td><td>大于等于</td><td></td></tr><tr><td></td><td><code>&lt;</code></td><td>小于</td><td></td></tr><tr><td></td><td><code>&lt;=</code></td><td>小于等于</td><td></td></tr><tr><td><strong>7</strong></td><td><code>==</code></td><td>等于</td><td>左到右</td></tr><tr><td></td><td><code>!=</code></td><td>不等于</td><td></td></tr><tr><td><strong>8</strong></td><td><code>&amp;</code></td><td>按位与</td><td>左到右</td></tr><tr><td><strong>9</strong></td><td><code>^</code></td><td>按位异或</td><td>左到右</td></tr><tr><td><strong>10</strong></td><td>\`</td><td>\`</td><td>按位或</td></tr><tr><td><strong>11</strong></td><td><code>&amp;&amp;</code></td><td>逻辑与</td><td>左到右</td></tr><tr><td><strong>12</strong></td><td>\`</td><td></td><td>\`</td></tr><tr><td><strong>13</strong></td><td><code>?:</code></td><td>条件运算符</td><td>右到左</td></tr><tr><td><strong>14</strong></td><td><code>=</code></td><td>赋值运算符</td><td>右到左</td></tr><tr><td></td><td><code>/=</code></td><td>除后赋值</td><td></td></tr><tr><td></td><td><code>*=</code></td><td>乘后赋值</td><td></td></tr><tr><td></td><td><code>%=</code></td><td>取模后赋值</td><td></td></tr><tr><td></td><td><code>+=</code></td><td>加后赋值</td><td></td></tr><tr><td></td><td><code>-=</code></td><td>减后赋值</td><td></td></tr><tr><td></td><td><code>&lt;&lt;=</code></td><td>左移后赋值</td><td></td></tr><tr><td></td><td><code>&gt;&gt;=</code></td><td>右移后赋值</td><td></td></tr><tr><td></td><td><code>&amp;=</code></td><td>按位与后赋值</td><td></td></tr><tr><td></td><td><code>^=</code></td><td>按位异或后赋值</td><td></td></tr><tr><td></td><td>\`</td><td>=\`</td><td>按位或后赋值</td></tr><tr><td><strong>15</strong></td><td><code>,</code></td><td>逗号运算符</td><td>左到右</td></tr></tbody></table><div class="warning custom-block github-alert"><p class="custom-block-title">WARNING</p><p></p><ul><li>① 不要过多的依赖运算符的优先级来控制表达式的执行顺序，这样可读性太差，尽量<code>使用小括号来控制</code>表达式的执行顺序。</li><li>② 不要把一个表达式写得过于复杂，如果一个表达式过于复杂，则把它<code>分成几步</code>来完成。</li><li>③ 运算符优先级不用刻意地去记忆，总体上：一元运算符 &gt; 算术运算符 &gt; 关系运算符 &gt; 逻辑运算符 &gt; 三元运算符 &gt; 赋值运算符。</li></ul></div><h1 id="第三章-附录" tabindex="-1">第三章：附录 <a class="header-anchor" href="#第三章-附录" aria-label="Permalink to &quot;第三章：附录&quot;">​</a></h1><h2 id="_3-1-字符集和字符集编码" tabindex="-1">3.1 字符集和字符集编码 <a class="header-anchor" href="#_3-1-字符集和字符集编码" aria-label="Permalink to &quot;3.1 字符集和字符集编码&quot;">​</a></h2><h3 id="_3-3-1-概述" tabindex="-1">3.3.1 概述 <a class="header-anchor" href="#_3-3-1-概述" aria-label="Permalink to &quot;3.3.1 概述&quot;">​</a></h3><ul><li>字符集和字符集编码（简称编码）计算机系统中处理文本数据的两个基本概念，它们密切相关但又有区别。</li><li>字符集（Character Set）是一组字符的集合，其中每个字符都被分配了一个<code>唯一的编号</code>（通常是数字）。字符可以是字母、数字、符号、控制代码（如换行符）等。<code>字符集定义了可以表示的字符的范围</code>，但它并不直接定义如何将这些字符存储在计算机中。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>ASCII（美国信息交换标准代码）是最早期和最简单的字符集之一，它只包括了英文字母、数字和一些特殊字符，共 128 个字符。每个字符都分配给了一个从 0 到 127 的数字。</p></div><ul><li>字符集编码（Character Encoding，简称编码）是一种方案或方法，<code>它定义了如何将字符集中的字符转换为计算机存储和传输的数据（通常是一串二进制数字）</code>。简而言之，编码是字符到二进制数据之间的映射规则。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>ASCII编码方案定义了如何将 ASCII 字符集中的每个字符表示为 7 位的二进制数字。例如：大写字母<code>&quot;A&quot;</code>在ASCII 编码中表示为二进制的<code>1000001</code>，十进制的 <code>65</code> 。</p></div><ul><li><code>字符集</code>和<code>字符集编码</code>之间的关系如下：</li></ul><p><img src="`+w+'" alt=""></p><ul><li>Linux 中安装帮助手册：</li></ul><p><img src="'+I+'" alt=""></p><h3 id="_3-3-2-ascii-编码" tabindex="-1">3.3.2 ASCII 编码 <a class="header-anchor" href="#_3-3-2-ascii-编码" aria-label="Permalink to &quot;3.3.2 ASCII 编码&quot;">​</a></h3><ul><li>从<code>冯·诺依曼</code>体系结构中，我们知道，计算机中所有的<code>数据</code>和<code>指令</code>都是以<code>二进制</code>的形式表示的；所以，计算机中对于文本数据的数据也是以二进制来存储的，那么对应的流程如下：</li></ul><p><img src="'+P+'" alt=""></p><ul><li>我们知道，计算机是上个世纪 60 年代在美国研制成功的，为了实现字符和二进制的转换，美国就制定了一套字符编码，即英语字符和二进制位之间的关系，即 ASCII （American Standard Code for Information Interchange）编码： <ul><li>ASCII 编码只包括了英文字符、数字和一些特殊字符，一共 128 个字符，并且每个字符都分配了唯一的数字，范围是 0 - 127。</li><li>ASCII 编码中的每个字符都使用 7 位的二进制数字表示；但是，计算机中的存储的最小单位是 1 B = 8 位，那么最高位统一规定为 0 。</li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 其实，早期是没有字符集的概念的，只是后来为了解决乱码问题，而产生了字符集的概念。</li><li>② 对于英文体系来说，<code>a-zA-Z0-9</code>以及一些<code>特殊字符</code>一共 <code>128</code> 就可以满足实际存储需求；所以，在也是为什么 ASCII 码使用 7 位二进制（2^7 = 128 ）来存储的。</li></ul></div><ul><li>在操作系统中，就内置了对应的编码表，Linux 也不例外；可以使用如下的命令查看：</li></ul><div class="language-shell vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">shell</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">man</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> ascii</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><p><img src="'+T+'" alt=""></p><ul><li>其对应的 ASCII 编码表，如下所示：</li></ul><p><img src="'+N+'" alt=""></p><ul><li>但是，随着计算机的发展，计算机开始了东征之路，由美国传播到东方：</li></ul><p><img src="'+L+'" alt=""></p><ul><li>先是传播到了欧洲，欧洲在兼容 ASCII 编码的基础上，推出了 ISO8859-1 编码，即： <ul><li>ISO8859-1 编码包括基本的拉丁字母表、数字、标点符号，以及西欧语言中特有的一些字符，如：法语中的 <code>è</code>、德语中的 <code>ü</code> 等。</li><li>ISO 8859-1 为每个字符分配一个单字节（8 位）编码，意味着它可以表示最多 256 （2^8）个不同的字符（编号从 0 到 255）。</li><li>ISO 8859-1 的前 128 个字符与 ASCII 编码完全一致，这使得 ASCII 编码的文本可以无缝转换为 ISO 8859-1 编码。</li></ul></li></ul><p><img src="'+O+'" alt=""></p><p><img src="'+S+'" alt=""></p><ul><li>计算机继续传播到了亚洲，亚洲（双字节）各个国家分别给出了自己国家对应的字符集编码，如： <ul><li>日本推出了 Shift-JIS 编码： <ul><li>单字节 ASCII 范围：0 - 127。</li><li>双字节范围： <ul><li>第一个字节：129 - 159 和 224 - 239 。</li><li>第二个字节：64 - 126 和 128 - 252 。</li></ul></li></ul></li><li>韩国推出了 EUC-KR 编码： <ul><li>单字节 ASCII 范围：0 - 127。</li><li>双字节范围：从 41281 - 65278。</li></ul></li><li>中国推出了 GBK 编码： <ul><li>单字节 ASCII 范围：0 - 127。</li><li>双字节范围：33088 - 65278 。</li></ul></li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 通过上面日本、韩国、中国的编码十进制范围，我们可以看到，虽然这些编码系统在技术上的编码范围存在重叠（特别是在高位字节区域），但因为它们各自支持的字符集完全不同，所以实际上它们并不直接冲突。</li><li>② 但是，如果一个中国人通过 GBK 编码写的文章，通过邮件发送给韩国人，因为韩国和中国在字符集编码上的高位字节有重叠部分，必然会造成歧义。</li></ul></div><h3 id="_3-3-3-unicode-编码" tabindex="-1">3.3.3 Unicode 编码 <a class="header-anchor" href="#_3-3-3-unicode-编码" aria-label="Permalink to &quot;3.3.3 Unicode 编码&quot;">​</a></h3><ul><li><p>在 Unicode 之前，世界上存在着数百种不同的编码系统，每一种编码系统都是为了支持特定语言或一组语言的字符集。这些编码系统，包括：ASCII、ISO 8859 系列、GBK、Shift-JIS、EUC-KR 等，它们各自有不同的字符范围和编码方式。这种多样性虽然在局部范围内解决了字符表示的问题，但也带来了以下几个方面的挑战：</p><ul><li><code>编码冲突</code>：由于不同的编码系统可以为相同的字节值分配不同的字符，因此在不同编码之间转换文本时，如果没有正确处理编码信息，就很容易产生乱码。这种编码冲突在尝试处理多种语言的文本时尤为突出。</li><li><code>编码的复杂性</code>：随着全球化的发展，软件和系统需要支持越来越多的语言，这就要求开发者和系统同时处理多种不同的编码系统。这不仅增加了开发和维护的复杂性，而且也增加了出错的风险。</li><li><code>资源限制</code>：在早期计算机技术中，内存和存储资源相对有限。不同的编码标准要求系统存储多套字符集数据，这无疑增加了对有限资源的消耗。</li><li>……</li></ul></li><li><p>针对上述的种种问题，为了推行全球化，Unicode 应运而生，Unicode 的核心规则和设计原则是建立一个全球统一的字符集，使得世界上所有的文字和符号都能被唯一地识别和使用，无论使用者位于何地或使用何种语言。这套规则包括了字符的编码、表示、处理和转换机制，旨在确保不同系统和软件间能够无缝交换和处理文本数据。</p><ul><li><code>通用字符集 (UCS)</code>：Unicode 为每一个字符分配一个唯一的编号（称为<code>“码点”</code>）。这些码点被组织在一个统一的字符集中，官方称之为 “通用字符集”（Universal Character Set，UCS）。码点通常表示为 <code>U+</code> 后跟一个十六进制数，例如：<code>U+0041</code> 代表大写的英文字母 <code>“A”</code>。</li><li><code>编码平面和区段</code>：Unicode 码点被划分为多个 “平面（Planes）”，每个平面包含 65536（16^4）个码点。目前，Unicode定义了 17 个平面（从 0 到16），每个平面被分配了一个编号，从 “基本多文种平面（BMP）” 的 0 开始，到 16 号平面结束。这意味着 Unicode 理论上可以支持超过 110万（17*65536）个码点。</li></ul></li><li><p>Unicode 仅仅只是字符集，给每个字符设置了唯一的数字编号而已，却没有给出这些数字编号实际如何存储，可以通过如下命令查看：</p></li></ul><p><img src="'+U+'" alt=""></p><ul><li>为了在计算机系统中表示 Unicode 字符，定义了几种编码方案，这些方案包括 UTF-8、UTF-16 和 UTF-32 等。 <ul><li><strong>UTF-8</strong>：使用 1 - 4 个字节表示每个 Unicode 字符，兼容 ASCII，是网络上最常用的编码。</li><li><strong>UTF-16</strong>：使用 2 - 4 个字节表示每个 Unicode 字符，适合于需要经常处理基本多文种平面之外字符的应用。</li><li><strong>UTF-32</strong>：使用固定的 4 个字节表示每个 Unicode 字符，简化了字符处理，但增加了存储空间的需求。</li></ul></li><li><code>Unicode 字符集</code>和对应的<code>UTF-8 字符编码</code>之间的关系，如下所示：</li></ul><p><img src="'+M+'" alt=""></p>',333),j=[R];function G(H,J,K,V,Z,W){return a(),i("div",null,j)}const Q=s(X,[["render",G]]);export{$ as __pageData,Q as default};

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import{_ as s,c as i,o as a,a5 as n}from"./chunks/framework.BE8if9e6.js";const l="/c/assets/1.L8V3GBrc.png",p="/c/assets/2.BkF1yWLn.png",h="/c/assets/3.CceY8r_n.png",t="/c/assets/4.DHaUgOwj.png",e="/c/assets/5.CXGaq_zh.png",k="/c/assets/6.BrZYAEEl.png",m=JSON.parse('{"title":"第一章：数据类型（⭐）","description":"","frontmatter":{},"headers":[],"relativePath":"notes/01_c-basic/03_xdx/index.md","filePath":"notes/01_c-basic/03_xdx/index.md","lastUpdated":1721208111000}'),r={name:"notes/01_c-basic/03_xdx/index.md"},d=n('<h1 id="第一章-数据类型-⭐" tabindex="-1">第一章：数据类型（⭐） <a class="header-anchor" href="#第一章-数据类型-⭐" aria-label="Permalink to &quot;第一章：数据类型（⭐）&quot;">​</a></h1><h2 id="_1-1-概述" tabindex="-1">1.1 概述 <a class="header-anchor" href="#_1-1-概述" aria-label="Permalink to &quot;1.1 概述&quot;">​</a></h2><ul><li><p>根据<code>变量</code>中<code>存储</code>的<code>值</code>的<code>不同</code>，我们可以将<code>变量</code>分为两类：</p><ul><li><code>普通变量</code>：变量所对应的内存中存储的是<code>普通值</code>。</li><li><code>指针变量</code>：变量所对应的内存中存储的是<code>另一个变量的地址</code>。</li></ul></li><li><p>如下图所示：</p></li></ul><p><img src="'+l+'" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>普通变量和指针变量的相同点：</p><ul><li>普通变量有内存空间，指针变量也有内存空间。</li><li>普通变量有内存地址，指针变量也有内存地址。</li><li>普通变量所对应的内存空间中有值，指针变量所对应的内存空间中也有值。</li></ul><p>普通变量和指针变量的不同点：</p><ul><li>普通变量所对应的内存空间存储的是普通的值，如：整数、小数、字符等；指针变量所对应的内存空间存储的是另外一个变量的地址。</li><li>普通变量有普通变量的运算方式，而指针变量有指针变量的运算方式（后续讲解）。</li></ul></div><ul><li>那么，在 C 语言中变量的数据类型就可以这么划分，如下所示：</li></ul><p><img src="'+p+`" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>根据<code>普通变量</code>中<code>存储</code>的<code>值</code>的类型不同，可以将<code>普通变量类型</code>划分为<code>基本数据类型</code>（整型、字符类型、浮点类型、布尔类型）和<code>复合数据类型</code>（数组类型、结构体类型、共用体类型、枚举类型）。</li><li>根据<code>指针变量</code>所<code>指向空间</code>中<code>存储</code>的<code>值</code>的类型不同，可以将<code>指针类型</code>分为<code>基本数据类型指针</code>、<code>复合数据类型指针</code>、<code>函数指针</code>、<code>数组指针</code>等，例如：如果指针所指向的空间保存的是 int 类型，那么该指针就是 int 类型的指针。</li></ul></div><h2 id="_1-2-整数类型" tabindex="-1">1.2 整数类型 <a class="header-anchor" href="#_1-2-整数类型" aria-label="Permalink to &quot;1.2 整数类型&quot;">​</a></h2><h3 id="_1-2-1-概述" tabindex="-1">1.2.1 概述 <a class="header-anchor" href="#_1-2-1-概述" aria-label="Permalink to &quot;1.2.1 概述&quot;">​</a></h3><ul><li>整数类型简称整型，用于存储整数值，如：12、20、50 等。</li><li>根据所占<code>内存空间</code>大小的不同，可以将整数类型划分为：</li><li>① 短整型：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间（内存空间）</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned short （无符号短整型）</td><td>2 字节</td><td>-32,768 (- 2^15) ~ 32,767 (2^15 -1)</td></tr><tr><td>[signed] short（有符号短整型，默认）</td><td>2 字节</td><td>0 ~ 65,535 (2^16 - 1)</td></tr></tbody></table><ul><li>② 整型：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间（内存空间）</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned int（无符号整型）</td><td>4 字节（通常）</td><td>-2147483648（- 2^31） ~ 2147483647 (2^31-1)</td></tr><tr><td>[signed] int（有符号整型，默认）</td><td>4 字节（通常）</td><td>0 ~ 4294967295 (0 ~2^32 -1)</td></tr></tbody></table><ul><li>③ 长整型：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间（内存空间）</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned long（无符号长整型）</td><td>4 字节（通常）</td><td>- 2^31 ~ 2^31-1</td></tr><tr><td>[signed] long（有符号长整型，默认）</td><td>4 字节（通常）</td><td>0 ~2^31 -1</td></tr></tbody></table><ul><li>④ 长长整型：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间（内存空间）</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned long long（无符号长整型）</td><td>8 字节（通常）</td><td>- 2^63 ~ 2^63-1</td></tr><tr><td>[signed] long long（有符号长整型，默认）</td><td>8 字节（通常）</td><td>0 ~2^34 -1</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① C 语言默认没有规定各种数据类型所占存储单元的长度，但是通常需要遵守：<code>sizeof(short int) ≤ sizeof(int) ≤ sizeof(long int) ≤ sizeof(long long)</code> ，具体的存储空间由编译系统自行决定；其中，sizeof 是测量类型或变量、常量长度的运算符。</li><li>② short 至少 2 个字节，long 至少 4 个字节。</li><li>③ 之所以这么规定，是为了可以让 C 语言长久使用，因为目前主流的 CPU 都是 64 位，但是在 C语言刚刚出现的时候，CPU 还是以 8 位和 16 位为主。如果那时候就将整型定死为 8 位或 16 位，那么现在我们肯定不会再学习 C 语言了。</li><li>④ 整型分为有符号 signed 和无符号 unsigned 两种，默认是 signed。</li><li>⑤ 在实际开发中，<code>最常用整型</code>就是 <code>int</code> 类型了，如果取值范围不够，就使用 long 或 long long 。</li><li>⑥ C 语言中的<code>格式占位符</code>非常多，只需要大致了解即可；因为，我们在实际开发中，一般都会使用 C++ 或 Rust 以及其它的高级编程语言，如：Java 等，早已经解决了需要通过<code>格式占位符</code>来输入和输出变量。</li></ul></div><h3 id="_1-2-2-短整型-了解" tabindex="-1">1.2.2 短整型（了解） <a class="header-anchor" href="#_1-2-2-短整型-了解" aria-label="Permalink to &quot;1.2.2 短整型（了解）&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 无符号短整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 有符号短整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 有符号表示的是正数、负数和 0 ，即有正负号。无符号表示的是 0 和正数，即正整数，没有符号。</li><li>② 在 <code>printf</code> 中<code>无符号短整型（unsigned short）</code>的<code>格式占位符</code>是 <code>%hu</code> ，<code>有符号短整型（signed short）</code>的<code>格式占位符</code>是 <code>%hd</code> 。</li><li>③ 可以通过 <code>sizeof</code> 运算符获取<code>无符号短整型（unsigned short）</code> 和 <code>有符号短整型（signed short）</code> 的<code>存储空间（所占内存空间）</code>。</li><li>③ 可以通过 <code>#include &lt;limits.h&gt;</code> 来获取 <code>无符号短整型（unsigned short）</code> 和<code>有符号短整型（signed short）</code>的<code>取值范围</code>。</li></ul></div><ul><li>示例：定义和打印短整型变量</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义有符号 short 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;s1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hd</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // s1 = -100</span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义无符号 short 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;s2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // s2 = 100</span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义 short 类型，默认是有符号</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">200</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;s3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hd</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // s3 = -200</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取存储空间</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned short 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 2</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;signed short 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 2</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;short 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 2</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned short 类型的范围是[0,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, USHRT_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [0,65535]</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;short 类型的范围是[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hd</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hd</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, SHRT_MIN,SHRT_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [-32768,32767]</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><h3 id="_1-2-3-整型" tabindex="-1">1.2.3 整型 <a class="header-anchor" href="#_1-2-3-整型" aria-label="Permalink to &quot;1.2.3 整型&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 无符号整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 有符号整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 有符号表示的是正数、负数和 0 ，即有正负号。无符号表示的是 0 和正数，即正整数，没有符号。</li><li>② 在 <code>printf</code> 中<code>无符号整型（unsigned int）</code>的<code>格式占位符</code>是 <code>%u</code> ，<code>有符号整型（signed int）</code>的<code>格式占位符</code>是 <code>%d</code> 。</li><li>③ 可以通过 <code>sizeof</code> 运算符获取<code>无符号整型（unsigned int）</code> 和 <code>有符号整型（signed int）</code> 的<code>存储空间（所占内存空间）</code>。</li><li>③ 可以通过 <code>#include &lt;limits.h&gt;</code> 来获取 <code>无符号整型（unsigned int）</code> 和<code>有符号整型（signed int）</code>的<code>取值范围</code>。</li></ul></div><ul><li>示例：定义和打印整型变量</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义有符号 int 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i1 = -100</span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义无符号 int 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%u</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i2 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义 int 类型，默认是有符号</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">200</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i3 = -200</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取存储空间</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned int 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;signed int 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;int 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned int 类型的范围是[0,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%u</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, UINT_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [0,4294967295]</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;int 类型的范围是[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, INT_MIN,INT_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [-2147483648,2147483647]</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><h3 id="_1-2-4-长整型-了解" tabindex="-1">1.2.4 长整型（了解） <a class="header-anchor" href="#_1-2-4-长整型-了解" aria-label="Permalink to &quot;1.2.4 长整型（了解）&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 无符号长整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 有符号长整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 有符号表示的是正数、负数和 0 ，即有正负号。无符号表示的是 0 和正数，即正整数，没有符号。</li><li>② 在 <code>printf</code> 中<code>无符号长整型（unsigned long）</code>的<code>格式占位符</code>是 <code>%lu</code> ，<code>有符号长整型（signed long）</code>的<code>格式占位符</code>是 <code>%ld</code> 。</li><li>③ 可以通过 <code>sizeof</code> 运算符获取<code>无符号长整型（unsigned long）</code> 和 <code>有符号长整型（signed long）</code> 的<code>存储空间（所占内存空间）</code>。</li><li>③ 可以通过 <code>#include &lt;limits.h&gt;</code> 来获取 <code>无符号长整型（unsigned long）</code> 和<code>有符号长整型（signed long）</code>的<code>取值范围</code>。</li></ul></div><ul><li>示例：定义和打印长整型变量</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义有符号 long 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> l1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;l1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%ld</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // l1 = -100</span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义无符号 long 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> l2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;l2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // l2 = 100</span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义 long 类型，默认是有符号</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> l3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">200</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;l3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%ld</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // l3 = -200</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取存储空间</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> l1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned long 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> l2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;signed long 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> l3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;long 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned long 类型的范围是[0,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ULONG_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [0,4294967295]</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;long 类型的范围是[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%ld</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%ld</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, LONG_MIN,LONG_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [-2147483648,2147483647]</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><h3 id="_1-2-5-长长整型-了解" tabindex="-1">1.2.5 长长整型（了解） <a class="header-anchor" href="#_1-2-5-长长整型-了解" aria-label="Permalink to &quot;1.2.5 长长整型（了解）&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 无符号长长整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 有符号长长整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 有符号表示的是正数、负数和 0 ，即有正负号。无符号表示的是 0 和正数，即正整数，没有符号。</li><li>② 在 <code>printf</code> 中<code>无符号长长整型（unsigned long long）</code>的<code>格式占位符</code>是 <code>%llu</code> ，<code>有符号长长整型（signed long long）</code>的<code>格式占位符</code>是 <code>%lld</code> 。</li><li>③ 可以通过 <code>sizeof</code> 运算符获取<code>无符号长长整型（unsigned long long）</code> 和 <code>有符号长长整型（signed long long）</code> 的<code>存储空间（所占内存空间）</code>。</li><li>③ 可以通过 <code>#include &lt;limits.h&gt;</code> 来获取 <code>无符号长长整型（unsigned long long）</code> 和<code>有符号长长整型（signed long long）</code>的<code>取值范围</code>。</li></ul></div><ul><li>示例：定义和打印长长整型变量</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义有符号 long long 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ll1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;ll1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lld</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // ll1 = -100</span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义无符号 long long 类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ll2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;ll2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%llu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // ll2 = 100</span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义 long long 类型，默认是有符号</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ll3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">200</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;ll3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lld</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // ll3 = -200</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取存储空间</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ll1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned long long 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 8</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ll2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;signed long long 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 8</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ll3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;long long 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 8</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned long long 类型的范围是[0,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%llu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ULLONG_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [0,18446744073709551615]</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;long long 类型的范围是[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lld</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lld</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, LLONG_MIN,LLONG_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [-9223372036854775808,9223372036854775807]</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><h3 id="_1-2-6-字面量后缀" tabindex="-1">1.2.6 字面量后缀 <a class="header-anchor" href="#_1-2-6-字面量后缀" aria-label="Permalink to &quot;1.2.6 字面量后缀&quot;">​</a></h3><ul><li><code>字面量</code>是<code>源代码</code>中一个<code>固定值</code>的<code>表示方法</code>，用于直接表示数据，即：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 100 就是字面量</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">L</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 100L 就是字面量</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">LL</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 100LL 就是字面量</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 默认情况下的，整数字面量的类型是 int 类型。</li><li>② 如果需要表示 long 类型的字面量，需要添加后缀 l 或 L ，建议 L。</li><li>③ 如果需要表示 long long类型的字面量，需要添加后缀 ll 或 LL，建议 LL 。</li><li>④ 如果需要表示无符号整数类型的字面量，需要添加 u 或 U，建议 U 。</li></ul></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">L</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%ld\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num2 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">LL</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lld\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num3 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num4 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">U</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num4 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%u\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num4);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num4 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num5 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">LU</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num5 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lu\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num5);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num5 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num6 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">ULL</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num6 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%llu\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num6);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num6 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br></div></div><h3 id="_1-2-7-精确宽度类型" tabindex="-1">1.2.7 精确宽度类型 <a class="header-anchor" href="#_1-2-7-精确宽度类型" aria-label="Permalink to &quot;1.2.7 精确宽度类型&quot;">​</a></h3><ul><li>在前文，我们了解到 C 语言的整数类型（short 、int、long、long long）在不同计算机上，占用的字节宽度可能不一样。但是，有的时候，我们希望整数类型的存储空间（字节宽度）是精确的，即：在任意平台（计算机）上都能一致，以提高程序的可移植性。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>Java 语言中的数据类型的存储空间（字节宽度）是一致的，这也是 Java 语言能够跨平台的重要原因之一（最主要的原因还是 JVM）。</li><li>在嵌入式开发中，使用精确宽度类型可以确保代码在各个平台上的一致性。</li></ul></div><ul><li>在 C 语言的标准头文件 <code>&lt;stdint.h&gt;</code> 中定义了一些新的类型别名，如下所示：</li></ul><table tabindex="0"><thead><tr><th>类型名称</th><th>含义</th></tr></thead><tbody><tr><td>int8_t</td><td>8 位有符号整数</td></tr><tr><td>int16_t</td><td>16 位有符号整数</td></tr><tr><td>int32_t</td><td>32 位有符号整数</td></tr><tr><td>int64_t</td><td>64 位有符号整数</td></tr><tr><td>uint8_t</td><td>8 位无符号整数</td></tr><tr><td>uint16_t</td><td>16 位无符号整数</td></tr><tr><td>uint32_t</td><td>32 位无符号整数</td></tr><tr><td>uint64_t64</td><td>64 位无符号整数</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>上面的这些类型都是类型别名，编译器会指定它们指向的底层类型，如：在某个系统中，如果 int 类型是 32 位，那么 int32_t 就会指向 int ；如果 long 类型是 32 位，那么 int32_t 就会指向 long。</p></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdint.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 变量 x32 声明为 int32_t 类型，可以保证是 32 位(4个字节)的宽度。</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int32_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x32 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 45933945</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;x32 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, x32);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // x32 = 45933945</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><h3 id="_1-2-8-sizeof-运算符" tabindex="-1">1.2.8 sizeof 运算符 <a class="header-anchor" href="#_1-2-8-sizeof-运算符" aria-label="Permalink to &quot;1.2.8 sizeof 运算符&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(表达式)</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 表达式可以是任何类型的数据类型、变量或常量。</li><li>② 返回某种数据类型或某个值占用的字节数量，并且 <code>sizeof(...)</code> 的<code>返回值类型</code>是 <code>size_t</code> 。</li><li>③ 在 <code>printf</code> 中使用占位符 <code>%zu</code> 来处理 <code>size_t</code> 类型的值。</li></ul></div><ul><li>示例：参数是数据类型</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stddef.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><ul><li>示例：参数是变量</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stddef.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(num);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><ul><li>示例：参数是常量</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stddef.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><h3 id="_1-2-9-数值溢出" tabindex="-1">1.2.9 数值溢出 <a class="header-anchor" href="#_1-2-9-数值溢出" aria-label="Permalink to &quot;1.2.9 数值溢出&quot;">​</a></h3><ul><li><p>所谓的数值溢出指的是：当超过一个数据类型能够存放的最大范围的时候，数值就会溢出。</p><ul><li>如果达到了最⼤值，再进行加法计算，数据就会超过该类型能够表示的最大值，叫做上溢出。</li><li>如果这个数⽬前是最小值，再进行减法计算， 数据就会超过该类型的最小值， 叫做下溢出。</li></ul></li><li><p>在 C 语言中，<code>整数</code>的<code>数据类型</code>分为<code>无符号</code>和<code>有符号</code>的，其在底层表示和存储是不一样的，即：</p><ul><li>无符号整数不使用最高位作为符号位，所有的位都用于表示数值，如：对于一个 4 位无符号整数，二进制表示的范围是从 0000 到 1111 ，那么十进制表示的范围是从 0 到 15。</li><li>有符号整数使用最高位作为符号位，这意味着它们可以表示正数和负数，通常使用补码来表示有符号整数。在补码表示法中：最高位为 0 表示正数、最高位为 1 表示负数，如：对于一个4位有符号整数，二进制表示的范围是从 0000（0） 到 0111 （7），1000 （-8）到 1111（-1）。</li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>在 C 语言中，无符号整数，最高位不是符号位，它只是数值的一部分。</li><li>在 C 语言中，有符号整数，最高位是符号位，用于表示正负数。</li></ul></div><ul><li><p>对于无符号的数值溢出：</p><ul><li>当数据到达最大值的时候，再加 1 就会回到无符号数的最小值。</li><li>当数据达到最小值的时候，再减 1 就会回到无符号数的最大值。</li></ul></li><li><p>那么，无符号的上溢出，原理就是这样的：</p></li></ul><p><img src="`+h+'" alt=""></p><ul><li>那么，无符号的下溢，原理就是这样的（需要先借位，然后再减）：</li></ul><p><img src="'+t+'" alt=""></p><ul><li><p>对于有符号的数值溢出：</p><ul><li>当数据到达最大值的时候，再加 1 就会回到有符号数的最小值。</li><li>当数据达到最小值的时候，再减 1 就会回到有符号数的最大值。</li></ul></li><li><p>那么，有符号的上溢出，原理就是这样的：</p></li></ul><p><img src="'+e+'" alt=""></p><ul><li>那么，有符号的下溢出，原理就是这样的：</li></ul><p><img src="'+k+`" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>在实际开发中，选择合适的数据类型，以避免数值溢出问题！！！</p></div><ul><li>示例：无符号的上溢出和下溢出</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> USHRT_MAX </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;无符号的上溢出 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 0</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;无符号的下溢出 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 65535</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><ul><li>示例：有符号的上溢出和下溢出</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> SHRT_MAX </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;有符号的上溢出 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hd</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // -32768</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> SHRT_MIN </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">-</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;有符号的下溢出 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hd</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 32767</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><h2 id="_1-3-浮点类型" tabindex="-1">1.3 浮点类型 <a class="header-anchor" href="#_1-3-浮点类型" aria-label="Permalink to &quot;1.3 浮点类型&quot;">​</a></h2><h2 id="_1-4-字符类型" tabindex="-1">1.4 字符类型 <a class="header-anchor" href="#_1-4-字符类型" aria-label="Permalink to &quot;1.4 字符类型&quot;">​</a></h2><h2 id="_1-5-布尔类型" tabindex="-1">1.5 布尔类型 <a class="header-anchor" href="#_1-5-布尔类型" aria-label="Permalink to &quot;1.5 布尔类型&quot;">​</a></h2><h2 id="_1-6-数据类型转换" tabindex="-1">1.6 数据类型转换 <a class="header-anchor" href="#_1-6-数据类型转换" aria-label="Permalink to &quot;1.6 数据类型转换&quot;">​</a></h2><h1 id="第二章-运算符" tabindex="-1">第二章：运算符 <a class="header-anchor" href="#第二章-运算符" aria-label="Permalink to &quot;第二章：运算符&quot;">​</a></h1><h2 id="_2-1-概述" tabindex="-1">2.1 概述 <a class="header-anchor" href="#_2-1-概述" aria-label="Permalink to &quot;2.1 概述&quot;">​</a></h2><h2 id="_2-2-算术运算符" tabindex="-1">2.2 算术运算符 <a class="header-anchor" href="#_2-2-算术运算符" aria-label="Permalink to &quot;2.2 算术运算符&quot;">​</a></h2><h2 id="_2-3-关系运算符-比较运算符" tabindex="-1">2.3 关系运算符（比较运算符） <a class="header-anchor" href="#_2-3-关系运算符-比较运算符" aria-label="Permalink to &quot;2.3 关系运算符（比较运算符）&quot;">​</a></h2><h2 id="_2-4-逻辑运算符" tabindex="-1">2.4 逻辑运算符 <a class="header-anchor" href="#_2-4-逻辑运算符" aria-label="Permalink to &quot;2.4 逻辑运算符&quot;">​</a></h2><h2 id="_2-5-位运算符" tabindex="-1">2.5 位运算符 <a class="header-anchor" href="#_2-5-位运算符" aria-label="Permalink to &quot;2.5 位运算符&quot;">​</a></h2><h2 id="_2-6-三元运算符" tabindex="-1">2.6 三元运算符 <a class="header-anchor" href="#_2-6-三元运算符" aria-label="Permalink to &quot;2.6 三元运算符&quot;">​</a></h2><h2 id="_2-7-运算符优先级" tabindex="-1">2.7 运算符优先级 <a class="header-anchor" href="#_2-7-运算符优先级" aria-label="Permalink to &quot;2.7 运算符优先级&quot;">​</a></h2>`,117),g=[d];function c(E,F,y,u,o,b){return a(),i("div",null,g)}const A=s(r,[["render",c]]);export{m as __pageData,A as default};

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<span class="line"><span>.idea</span></span>
<span class="line"><span>cmake-build-*</span></span>
<span class="line"><span>build</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br></div></div><h2 id="_7-6-演示" tabindex="-1">7.6 演示 <a class="header-anchor" href="#_7-6-演示" aria-label="Permalink to &quot;7.6 演示&quot;">​</a></h2><ul><li>我们可以在项目中，临时创建或复制一个文件，看上述配置是否生效，即：</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>如果是复制并粘贴一个文件到项目中，请点击<code>重新加载 CMake 项目</code>！！！</p></div><p><img src="/c/assets/158.C1t2T6FV.gif" alt=""></p><h1 id="第八章-c-语言的编译过程-⭐" tabindex="-1">第八章：C 语言的编译过程（⭐） <a class="header-anchor" href="#第八章-c-语言的编译过程-⭐" aria-label="Permalink to &quot;第八章：C 语言的编译过程（⭐）&quot;">​</a></h1><h2 id="_8-1-概述" tabindex="-1">8.1 概述 <a class="header-anchor" href="#_8-1-概述" aria-label="Permalink to &quot;8.1 概述&quot;">​</a></h2><ul><li>C 程序的编译过程，如下所示：</li></ul><p><img src="/c/assets/159.Rqa4uHq6.png" alt=""></p><ul><li>过程 ① ：编写（编辑）源代码，即：编写 C 语言源程序代码，并以文件的形式存储在磁盘中。</li></ul><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><p>源程序需要以 <code>.c</code> 作为扩展名。</p></div><ul><li>过程 ② ：编译，即：将 C 语言源程序转换为<code>目标程序（或目标文件）</code>。如果程序没有错误，没有任何提示，就会生成一个扩展名为 <code>.obj</code>或 <code>.o</code> 的二进制文件。C 语言中的每条可执行语句经过编译之后，最终都会转换为二进制的机器指令。</li></ul><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><ul><li><p>① 其实，<code>编译阶段</code>包含了<code>预处理</code>、<code>编译</code>和<code>汇编</code>。</p></li><li><p>② <code>预处理</code>是编译过程的第一个阶段。在这个阶段，预处理器处理源代码中的指令（例如：<code>#include</code>、<code>#define</code>等），主要任务包括：</p><ul><li><p><strong>头文件包含</strong>：将头文件的内容插入到源文件中。例如：<code>#include &lt;stdio.h&gt;</code>会被替换为<code>stdio.h</code>文件的内容。</p></li><li><p><strong>宏展开</strong>：替换宏定义。例如：<code>#define PI 3.14</code>会将代码中的<code>PI</code>替换为<code>3.14</code>。</p></li><li><p><strong>条件编译</strong>：根据条件指令（如：<code>#ifdef</code>、<code>#ifndef</code>）有选择地编译代码。</p></li><li><p><strong>删除代码中的注释，但是不会进行语法检查</strong>。</p></li><li><p>预处理完成后，生成一个扩展名为<code>.i</code>的中间文件。</p></li></ul></li><li><p>③ <code>编译</code>是将预处理后的源代码转换为汇编代码的过程。在这个阶段，编译器会检查代码的语法和语义，将其转换为目标机器的汇编语言，生成一个扩展名为<code>.s</code>的汇编文件。</p></li><li><p>④ <code>汇编</code>是将汇编代码转换为机器代码（也称为目标代码或目标文件）的过程。在这个阶段，汇编器将汇编指令转换为二进制机器指令，生成一个扩展名为<code>.o</code>或 <code>.obj</code>的目标文件。</p></li></ul></div><ul><li>过程 ③ ：链接（连接），即：将编译形成的目标文件 <code>*.obj</code> 或 <code>*.o</code>和库函数以及其他目录文件<code>链接</code>，形成一个统一的二进制文件 <code>*.exe</code>。</li></ul><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><ul><li>为什么需要链接库文件？</li><li>因为我们的 C 程序会使用 C 程序库中的内容，如：<code>&lt;stdio.h&gt;</code> 中的 <code>printf()</code> 函数，这些函数不是程序员自己写的，而是 C 程序库中提供的，因此需要链接。其实，在链接过程中，还会加入启动代码，这个启动代码（和系统相关，Linux 下主要有 crt0.c、crti.c 等，它们设置堆栈后，再调用 main() 函数）负责初始化程序运行时的环境。</li></ul></div><ul><li>过程 ④ ：执行，即：有了可执行的 <code>*.exe</code>文件，我们就可以在控制台上执行运行此 <code>*.exe</code> 文件。</li></ul><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><p>如果<code>修改</code>了源代码，还需要重新<code>编译</code>、<code>链接</code>，并生成新的 <code>*.exe</code>文件，再执行，方能生效。</p></div><h2 id="_8-2-gcc-编译器的介绍" tabindex="-1">8.2 GCC 编译器的介绍 <a class="header-anchor" href="#_8-2-gcc-编译器的介绍" aria-label="Permalink to &quot;8.2 GCC 编译器的介绍&quot;">​</a></h2><ul><li>编辑器，如：vim 、vscode 等，是指我们用它来编写源程序的（编辑代码），而我们写的代码语句，电脑是不懂的，我们需要把它转成电脑能懂的语句，编译器就是这样的转化工具。换言之，我们用编辑器编写程序，由编译器编译后才可以运行！</li><li>编译器是将易于编写、阅读和维护的高级计算机语言翻译为计算机能解读、运行的低级机器语言的程序。</li><li>gcc（GNU Compiler Collection，GNU 编译器套件），是由 GNU 开发的编程语言编译器。gcc 原本作为 GNU 操作系统的官方编译器，现已被大多数类 Unix 操作系统（如：Linux、BSD、Mac OS X 等）采纳为标准的编译器，gcc 同样适用于微软的 Windows 。</li><li>gcc 最初用于编译 C 语言，随着项目的发展， gcc 已经成为了能够编译 C、C++、Java、Ada、fortran、Object C、Object C++、Go 语言的编译器大家族。</li></ul><h2 id="_8-3-通过-gcc-直接生成可执行文件" tabindex="-1">8.3 通过 gcc 直接生成可执行文件 <a class="header-anchor" href="#_8-3-通过-gcc-直接生成可执行文件" aria-label="Permalink to &quot;8.3 通过 gcc 直接生成可执行文件&quot;">​</a></h2><ul><li>示例：进行预处理、编译、汇编和链接</li></ul><div class="language-shell vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">shell</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">gcc</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> HelloWorld.c</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> -o</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> HelloWorld.exe</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><p><img src="/c/assets/160.6yQYnjOa.gif" alt=""></p><h2 id="_8-4-通过-gcc-分步编译" tabindex="-1">8.4 通过 gcc 分步编译 <a class="header-anchor" href="#_8-4-通过-gcc-分步编译" aria-label="Permalink to &quot;8.4 通过 gcc 分步编译&quot;">​</a></h2><h3 id="_8-3-1-概述" tabindex="-1">8.3.1 概述 <a class="header-anchor" href="#_8-3-1-概述" aria-label="Permalink to &quot;8.3.1 概述&quot;">​</a></h3><ul><li>预处理命令：</li></ul><div class="language-shell vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">shell</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">gcc</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> -E</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 源文件.c</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> -o</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 源文件.i</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> # 通常以 .i 结尾表示这个文件是一个中间状态</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><ul><li>编译（预处理和编译）命令：</li></ul><div class="language-shell vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">shell</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">gcc</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> -S</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 源文件.i</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> -o</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 源文件.s</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> # 在 Linux 中，通常以 .s 结尾；在 Windows 中，通常以 .asm 结尾</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><ul><li>汇编（预处理、编译和汇编）命令：</li></ul><div class="language-shell vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">shell</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">gcc</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> -c</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 源文件.s</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> -o</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 源文件.o</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> # 在 Linux 中，通常以 .o 结尾；在 Windows 中，通常以 .obj 结尾</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><ul><li>链接（预处理、编译、汇编和链接）命令：</li></ul><div class="language-shell vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">shell</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">gcc</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 源文件.o</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> -o</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 源文件.exe</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> # 在 Linux 中，通常以 .out 结尾；在 Windows 中，通常以 .exe 结尾</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><h3 id="_8-4-2-应用示例" tabindex="-1">8.4.2 应用示例 <a class="header-anchor" href="#_8-4-2-应用示例" aria-label="Permalink to &quot;8.4.2 应用示例&quot;">​</a></h3><ul><li>示例：只进行预处理</li></ul><div class="language-shell vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">shell</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">gcc</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> -E</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> HelloWorld.c</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> -o</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> HelloWorld.i</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><p><img src="/c/assets/161.hYR9GiiD.gif" alt=""></p><ul><li>示例：只进行预处理和编译</li></ul><div class="language-shell vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">shell</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">gcc</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> -S</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> HelloWorld.i</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> -o</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> HelloWorld.s</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><p><img src="/c/assets/162.D3b-QIrA.gif" alt=""></p><ul><li>示例：只进行预处理、编译和汇编</li></ul><div class="language-shell vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">shell</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">gcc</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> -c</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> HelloWorld.s</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> -o</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> HelloWorld.o</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><p><img src="/c/assets/163.DGbA6qsW.gif" alt=""></p><ul><li>示例：进行预处理、编译、汇编和链接</li></ul><div class="language-shell vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">shell</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">gcc</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> HelloWorld.o</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> -o</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> HelloWorld.exe</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><p><img src="/c/assets/164.BToOkxf2.gif" 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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><h2 id="_3-3-进制的转换" tabindex="-1">3.3 进制的转换 <a class="header-anchor" href="#_3-3-进制的转换" aria-label="Permalink to &quot;3.3 进制的转换&quot;">​</a></h2><h3 id="_3-3-1-概述" tabindex="-1">3.3.1 概述 <a class="header-anchor" href="#_3-3-1-概述" aria-label="Permalink to &quot;3.3.1 概述&quot;">​</a></h3><ul><li>不同进制的转换，如下所示：</li></ul><p><img src="/c/assets/19.uqLiL_yu.png" alt=""></p><ul><li>在计算机中，数据是从右往左的方式排列的；其中，最右边的是低位，最左边的是高位，即：</li></ul><p><img src="/c/assets/20.CkykpHY2.png" alt=""></p><h3 id="_3-3-2-二进制和十进制的转换" tabindex="-1">3.3.2 二进制和十进制的转换 <a class="header-anchor" href="#_3-3-2-二进制和十进制的转换" aria-label="Permalink to &quot;3.3.2 二进制和十进制的转换&quot;">​</a></h3><h4 id="_3-3-2-1-二进制转换为十进制" tabindex="-1">3.3.2.1 二进制转换为十进制 <a class="header-anchor" href="#_3-3-2-1-二进制转换为十进制" aria-label="Permalink to &quot;3.3.2.1 二进制转换为十进制&quot;">​</a></h4><ul><li>规则：从最低位开始，将每个位上的数提取出来，乘以 2 的 （位数 - 1 ）次方，然后求和。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 在学术界，将这种计算规则，称为<code>位权相加法</code>。</li><li>② <code>八进制转换为十进制</code>、<code>十六进制转换为十进制</code>和<code>二进制转换为十进制</code>的算法相同！！！</li></ul></div><ul><li>示例：十进制转十进制</li></ul><p><img src="/c/assets/21.DV1YbrOP.png" alt=""></p><ul><li>示例：二进制转十进制</li></ul><p><img src="/c/assets/22.AHNJT9TV.png" alt=""></p><h4 id="_3-3-2-2-十进制转换二进制" tabindex="-1">3.3.2.2 十进制转换二进制 <a class="header-anchor" href="#_3-3-2-2-十进制转换二进制" aria-label="Permalink to &quot;3.3.2.2 十进制转换二进制&quot;">​</a></h4><ul><li>规则：将该数不断除以 2 ，直到商为 0 为止，然后将每步得到的余数倒过来，就是对应的二进制。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 在学术界，将这种计算规则，称为<code>短除法</code>或<code>连续除2取余法</code>。</li><li>② 很好理解，只有不断地除以 2 ，就能保证最大的数字不超过 2 ，这不就是二进制（只能有 0 或 1）吗？</li><li>③ <code>八进制转换为二进制</code>、<code>十六进制转换为二进制</code>和<code>十进制转换为二进制</code>的算法相同！！！</li></ul></div><ul><li>示例：十进制转十进制</li></ul><p><img src="/c/assets/23.Bs-MOwx2.png" alt=""></p><ul><li>示例：十进制转二进制</li></ul><p><img src="/c/assets/24.StzjmBz-.png" alt=""></p><h3 id="_3-3-3-二进制转八进制" tabindex="-1">3.3.3 二进制转八进制 <a class="header-anchor" href="#_3-3-3-二进制转八进制" aria-label="Permalink to &quot;3.3.3 二进制转八进制&quot;">​</a></h3><ul><li><p>规则：每 3 位二进制就是一个八进制。</p></li><li><p>示例：011 101 001 -&gt; 351</p></li></ul><p><img src="/c/assets/25.C0wVWaxD.png" alt=""></p><h3 id="_3-3-4-二进制转十六进制" tabindex="-1">3.3.4 二进制转十六进制 <a class="header-anchor" href="#_3-3-4-二进制转十六进制" aria-label="Permalink to &quot;3.3.4 二进制转十六进制&quot;">​</a></h3><ul><li><p>规则：每 4 位二进制就是一个十六进制。</p></li><li><p>示例：1110 1001 -&gt; 0xE9</p></li></ul><p><img src="/c/assets/26.LXJMAihe.png" alt=""></p><h2 id="_3-4-原码、反码和补码" tabindex="-1">3.4 原码、反码和补码 <a class="header-anchor" href="#_3-4-原码、反码和补码" aria-label="Permalink to &quot;3.4 原码、反码和补码&quot;">​</a></h2><h3 id="_3-4-1-概述" tabindex="-1">3.4.1 概述 <a class="header-anchor" href="#_3-4-1-概述" aria-label="Permalink to &quot;3.4.1 概述&quot;">​</a></h3><ul><li>机器数：一个数在计算机的存储形式是二进制，我们称这些二进制数为机器数。机器数可以是有符号的，用机器数的最高位来存放符号位，0 表示正数，1 表示负数。</li></ul><p><img src="/c/assets/27._UTCq3PD.png" alt=""></p><ul><li>真值：因为机器数带有符号位，所以机器数的形式值不等于其真实表示的值（真值），以机器数 1000 0001 为例，其真正表示的值（首位是符号位）为 -1，而形式值却是 129 ，因此将带有符号位的机器数的真正表示的值称为机器数的真值。</li></ul><p><img src="/c/assets/28.BjQ5kBL-.png" alt=""></p><h3 id="_3-4-2-原码" tabindex="-1">3.4.2 原码 <a class="header-anchor" href="#_3-4-2-原码" aria-label="Permalink to &quot;3.4.2 原码&quot;">​</a></h3><ul><li>原码的表示与机器数真值表示的一样，即用第一位表示符号，其余位表示数值。</li><li>规则： <ul><li>正数的<code>原码</code>是它本身对应的二进制数，符号位是 0 。</li><li>负数的<code>原码</code>是它本身绝对值对应的二进制数，但是符号位是 1 。</li></ul></li><li>+1 的原码，使用 8 位二进数来表示，就是：</li></ul><table tabindex="0"><thead><tr><th>十进制数</th><th>原码（8位二进制数）</th></tr></thead><tbody><tr><td>+1</td><td><code>0</code>000 0001</td></tr></tbody></table><ul><li>-1 的原码，使用 8 位二进数来表示，就是：</li></ul><table tabindex="0"><thead><tr><th>十进制数</th><th>原码（8位二进制数）</th></tr></thead><tbody><tr><td>-1</td><td><code>1</code>000 0001</td></tr></tbody></table><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><p>按照原码的规则，会出现 <code>+0</code> 和 <code>-0</code> 的情况，即：<code>0</code>000 0000（+0）、<code>1</code>000 0000（-0），显然不符合实际情况；所以，计算机底层虽然存储和计算的都是二进数，但显然不是原码。</p></div><h3 id="_3-4-3-反码" tabindex="-1">3.4.3 反码 <a class="header-anchor" href="#_3-4-3-反码" aria-label="Permalink to &quot;3.4.3 反码&quot;">​</a></h3><ul><li><p>规则：</p><ul><li>正数的反码和它的原码相同。</li><li>负数的反码是在其原码的基础上，符号位不变，其余各位取反。</li></ul></li><li><p>+1 的反码，使用 8 位二进数来表示，就是：</p></li></ul><table tabindex="0"><thead><tr><th>十进制数</th><th>原码（8位二进制数）</th><th>反码（8位二进制数）</th></tr></thead><tbody><tr><td>+1</td><td><code>0</code>000 0001</td><td><code>0</code>000 0001</td></tr></tbody></table><ul><li>-1 的反码，使用 8 位二进数来表示，就是：</li></ul><table tabindex="0"><thead><tr><th>十进制数</th><th>原码（8位二进制数）</th><th>反码（8位二进制数）</th></tr></thead><tbody><tr><td>-1</td><td><code>1</code>000 0001</td><td><code>1</code>111 1110</td></tr></tbody></table><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><p>按照反码的规则，如果是 <code>+0</code>，对应的原码是 <code>0</code>000 0000；那么，其反码还是 <code>0</code>000 0000 ；如果是 <code>-0</code>，对应的原码是 <code>1</code>000 0000，其反码是 <code>1</code>111 1111，显然不符合实际情况；所以，计算机底层虽然存储和计算的都是二进数，但显然不是反码。</p></div><h3 id="_3-4-4-补码" tabindex="-1">3.4.4 补码 <a class="header-anchor" href="#_3-4-4-补码" aria-label="Permalink to &quot;3.4.4 补码&quot;">​</a></h3><ul><li><p>规则：</p><ul><li>正数的补码和它的原码相同。</li><li>负数的补码是在其反码的基础上 + 1 。</li></ul></li><li><p>+1 的补码，使用 8 位二进数来表示，就是：</p></li></ul><table tabindex="0"><thead><tr><th>十进制数</th><th>原码（8位二进制数）</th><th>反码（8位二进制数）</th><th>补码（8位二进制数）</th></tr></thead><tbody><tr><td>+1</td><td><code>0</code>000 0001</td><td><code>0</code>000 0001</td><td><code>0</code>000 0001</td></tr></tbody></table><ul><li>-1 的补码，使用 8 位二进数来表示，就是：</li></ul><table tabindex="0"><thead><tr><th>十进制数</th><th>原码（8位二进制数）</th><th>反码（8位二进制数）</th><th>补码（8位二进制数）</th></tr></thead><tbody><tr><td>-1</td><td><code>1</code>000 0001</td><td><code>1</code>111 1110</td><td><code>1</code>111 1111</td></tr></tbody></table><ul><li>如果 0 ，按照 <code>+0</code> 的情况进行处理，即：</li></ul><p><img src="/c/assets/29.COIOzcmT.png" alt=""></p><ul><li>如果 0 ，按照 <code>-0</code> 的情况进行处理，即：</li></ul><p><img src="/c/assets/30.Cu__mjav.png" alt=""></p><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><ul><li>① 补码表示法解决了<code>原码</code>和<code>反码</code>存在的<code>两种</code>零（<code>+0</code> 和 <code>-0</code>）的问题，即：在补码表示法中，只有<code>一个</code>零，即 0000 0000。</li><li>②补码使得<code>加法运算</code>和<code>减法运算</code>可以统一处理，通过将减法运算<code>转换</code>为加法运算，可以简化硬件设计，提高了运算效率。</li><li>③ 计算机底层<code>存储</code>和<code>计算</code>的都是<code>二进数的补码</code>。</li></ul></div><h3 id="_3-4-5-总结" tabindex="-1">3.4.5 总结 <a class="header-anchor" href="#_3-4-5-总结" aria-label="Permalink to &quot;3.4.5 总结&quot;">​</a></h3><ul><li>① 正数的原码、反码和补码都是一样的，三码合一。</li><li>② 负数的反码是在其原码的基础上，按位取反（0 变 1 ，1 变 0 ），符号位不变；负数的补码是其反码 + 1 。</li><li>③ 0 的补码是 0 。</li></ul><h2 id="_3-5-计算机底层为什么使用补码" tabindex="-1">3.5 计算机底层为什么使用补码？ <a class="header-anchor" href="#_3-5-计算机底层为什么使用补码" aria-label="Permalink to &quot;3.5 计算机底层为什么使用补码？&quot;">​</a></h2><ul><li>如果计算是 <code>2 - 2</code> ，那么可以转换为 <code>2 + (-2)</code>，这样计算机内部在处理<code>减法计算</code>的时候，就会将其转换为<code>加法计算</code>的形式，以简化硬件设计和提高计算效率。</li><li><code>最高位</code>表示<code>符号位</code>，由于符号位的存在，如果使用<code>原码</code>来计算，就会导致<code>计算结果不正确</code>，即：</li></ul><p><img src="/c/assets/31.BX_KzkHt.png" alt=""></p><ul><li><code>补码</code>的设计可以巧妙的让<code>符号位</code>也参与计算，并且可以得到<code>正确的计算结果</code>，即：</li></ul><p><img src="/c/assets/32.COt_QxSP.png" alt=""></p></div></div></main><footer class="VPDocFooter" data-v-39a288b8 data-v-d4a0bba5><!--[--><!--]--><div class="edit-info" data-v-d4a0bba5><!----><div class="last-updated" data-v-d4a0bba5><p class="VPLastUpdated" data-v-d4a0bba5 data-v-7e05ebdb>上次更新: <time datetime="2024-07-17T07:44:31.000Z" data-v-7e05ebdb></time></p></div></div><nav class="prev-next" aria-labelledby="doc-footer-aria-label" data-v-d4a0bba5><span class="visually-hidden" id="doc-footer-aria-label" data-v-d4a0bba5>Pager</span><div class="pager" data-v-d4a0bba5><a class="VPLink link pager-link prev" href="/c/notes/01_c-basic/01_xdx/" 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class="spacer" data-v-3f215769></div><!--[--><!--]--><!----><!--[--><!--]--><!--[--><!--]--></div></div></div></div><div class="content" data-v-39a288b8><div class="content-container" data-v-39a288b8><!--[--><!--]--><main class="main" data-v-39a288b8><div style="position:relative;" class="vp-doc _c_notes_01_c-basic_03_xdx_" data-v-39a288b8><div><h1 id="第一章-数据类型-⭐" tabindex="-1">第一章：数据类型（⭐） <a class="header-anchor" href="#第一章-数据类型-⭐" aria-label="Permalink to &quot;第一章：数据类型（⭐）&quot;">​</a></h1><h2 id="_1-1-概述" tabindex="-1">1.1 概述 <a class="header-anchor" href="#_1-1-概述" aria-label="Permalink to &quot;1.1 概述&quot;">​</a></h2><ul><li><p>根据<code>变量</code>中<code>存储</code>的<code>值</code>的<code>不同</code>，我们可以将<code>变量</code>分为两类：</p><ul><li><code>普通变量</code>：变量所对应的内存中存储的是<code>普通值</code>。</li><li><code>指针变量</code>：变量所对应的内存中存储的是<code>另一个变量的地址</code>。</li></ul></li><li><p>如下图所示：</p></li></ul><p><img src="/c/assets/1.L8V3GBrc.png" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>普通变量和指针变量的相同点：</p><ul><li>普通变量有内存空间，指针变量也有内存空间。</li><li>普通变量有内存地址，指针变量也有内存地址。</li><li>普通变量所对应的内存空间中有值，指针变量所对应的内存空间中也有值。</li></ul><p>普通变量和指针变量的不同点：</p><ul><li>普通变量所对应的内存空间存储的是普通的值，如：整数、小数、字符等；指针变量所对应的内存空间存储的是另外一个变量的地址。</li><li>普通变量有普通变量的运算方式，而指针变量有指针变量的运算方式（后续讲解）。</li></ul></div><ul><li>那么，在 C 语言中变量的数据类型就可以这么划分，如下所示：</li></ul><p><img src="/c/assets/2.BkF1yWLn.png" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>根据<code>普通变量</code>中<code>存储</code>的<code>值</code>的类型不同，可以将<code>普通变量类型</code>划分为<code>基本数据类型</code>（整型、字符类型、浮点类型、布尔类型）和<code>复合数据类型</code>（数组类型、结构体类型、共用体类型、枚举类型）。</li><li>根据<code>指针变量</code>所<code>指向空间</code>中<code>存储</code>的<code>值</code>的类型不同，可以将<code>指针类型</code>分为<code>基本数据类型指针</code>、<code>复合数据类型指针</code>、<code>函数指针</code>、<code>数组指针</code>等，例如：如果指针所指向的空间保存的是 int 类型，那么该指针就是 int 类型的指针。</li></ul></div><h2 id="_1-2-整数类型" tabindex="-1">1.2 整数类型 <a class="header-anchor" href="#_1-2-整数类型" aria-label="Permalink to &quot;1.2 整数类型&quot;">​</a></h2><h3 id="_1-2-1-概述" tabindex="-1">1.2.1 概述 <a class="header-anchor" href="#_1-2-1-概述" aria-label="Permalink to &quot;1.2.1 概述&quot;">​</a></h3><ul><li>整数类型简称整型，用于存储整数值，如：12、20、50 等。</li><li>根据所占<code>内存空间</code>大小的不同，可以将整数类型划分为：</li><li>① 短整型：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间（内存空间）</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned short （无符号短整型）</td><td>2 字节</td><td>-32,768 (- 2^15) ~ 32,767 (2^15 -1)</td></tr><tr><td>[signed] short（有符号短整型，默认）</td><td>2 字节</td><td>0 ~ 65,535 (2^16 - 1)</td></tr></tbody></table><ul><li>② 整型：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间（内存空间）</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned int（无符号整型）</td><td>4 字节（通常）</td><td>-2147483648（- 2^31） ~ 2147483647 (2^31-1)</td></tr><tr><td>[signed] int（有符号整型，默认）</td><td>4 字节（通常）</td><td>0 ~ 4294967295 (0 ~2^32 -1)</td></tr></tbody></table><ul><li>③ 长整型：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间（内存空间）</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned long（无符号长整型）</td><td>4 字节（通常）</td><td>- 2^31 ~ 2^31-1</td></tr><tr><td>[signed] long（有符号长整型，默认）</td><td>4 字节（通常）</td><td>0 ~2^31 -1</td></tr></tbody></table><ul><li>④ 长长整型：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间（内存空间）</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned long long（无符号长整型）</td><td>8 字节（通常）</td><td>- 2^63 ~ 2^63-1</td></tr><tr><td>[signed] long long（有符号长整型，默认）</td><td>8 字节（通常）</td><td>0 ~2^34 -1</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① C 语言默认没有规定各种数据类型所占存储单元的长度，但是通常需要遵守：<code>sizeof(short int) ≤ sizeof(int) ≤ sizeof(long int) ≤ sizeof(long long)</code> ，具体的存储空间由编译系统自行决定；其中，sizeof 是测量类型或变量、常量长度的运算符。</li><li>② short 至少 2 个字节，long 至少 4 个字节。</li><li>③ 之所以这么规定，是为了可以让 C 语言长久使用，因为目前主流的 CPU 都是 64 位，但是在 C语言刚刚出现的时候，CPU 还是以 8 位和 16 位为主。如果那时候就将整型定死为 8 位或 16 位，那么现在我们肯定不会再学习 C 语言了。</li><li>④ 整型分为有符号 signed 和无符号 unsigned 两种，默认是 signed。</li><li>⑤ 在实际开发中，<code>最常用整型</code>就是 <code>int</code> 类型了，如果取值范围不够，就使用 long 或 long long 。</li><li>⑥ C 语言中的<code>格式占位符</code>非常多，只需要大致了解即可；因为，我们在实际开发中，一般都会使用 C++ 或 Rust 以及其它的高级编程语言，如：Java 等，早已经解决了需要通过<code>格式占位符</code>来输入和输出变量。</li></ul></div><h3 id="_1-2-2-短整型-了解" tabindex="-1">1.2.2 短整型（了解） <a class="header-anchor" href="#_1-2-2-短整型-了解" aria-label="Permalink to &quot;1.2.2 短整型（了解）&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 无符号短整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 有符号短整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 有符号表示的是正数、负数和 0 ，即有正负号。无符号表示的是 0 和正数，即正整数，没有符号。</li><li>② 在 <code>printf</code> 中<code>无符号短整型（unsigned short）</code>的<code>格式占位符</code>是 <code>%hu</code> ，<code>有符号短整型（signed short）</code>的<code>格式占位符</code>是 <code>%hd</code> 。</li><li>③ 可以通过 <code>sizeof</code> 运算符获取<code>无符号短整型（unsigned short）</code> 和 <code>有符号短整型（signed short）</code> 的<code>存储空间（所占内存空间）</code>。</li><li>③ 可以通过 <code>#include &lt;limits.h&gt;</code> 来获取 <code>无符号短整型（unsigned short）</code> 和<code>有符号短整型（signed short）</code>的<code>取值范围</code>。</li></ul></div><ul><li>示例：定义和打印短整型变量</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
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data-v-b8d55f3b>Linux 高并发服务器开发</p><!----></div><!----></div></div><!--]--><!--[--><!--]--></nav></aside><div class="VPContent has-sidebar" id="VPContent" data-v-5d98c3a5 data-v-1428d186><div class="VPDoc has-sidebar has-aside" data-v-1428d186 data-v-39a288b8><!--[--><!--]--><div class="container" data-v-39a288b8><div class="aside" data-v-39a288b8><div class="aside-curtain" data-v-39a288b8></div><div class="aside-container" data-v-39a288b8><div class="aside-content" data-v-39a288b8><div class="VPDocAside" data-v-39a288b8 data-v-3f215769><!--[--><!--]--><!--[--><!--]--><nav aria-labelledby="doc-outline-aria-label" class="VPDocAsideOutline" data-v-3f215769 data-v-a5bbad30><div class="content" data-v-a5bbad30><div class="outline-marker" data-v-a5bbad30></div><div aria-level="2" class="outline-title" id="doc-outline-aria-label" role="heading" data-v-a5bbad30>目录</div><ul class="VPDocOutlineItem root" data-v-a5bbad30 data-v-b933a997><!--[--><!--]--></ul></div></nav><!--[--><!--]--><div class="spacer" data-v-3f215769></div><!--[--><!--]--><!----><!--[--><!--]--><!--[--><!--]--></div></div></div></div><div class="content" data-v-39a288b8><div class="content-container" data-v-39a288b8><!--[--><!--]--><main class="main" data-v-39a288b8><div style="position:relative;" class="vp-doc _c_notes_01_c-basic_03_xdx_" data-v-39a288b8><div><h1 id="第一章-数据类型-⭐" tabindex="-1">第一章：数据类型（⭐） <a class="header-anchor" href="#第一章-数据类型-⭐" aria-label="Permalink to &quot;第一章：数据类型（⭐）&quot;">​</a></h1><h2 id="_1-1-概述" tabindex="-1">1.1 概述 <a class="header-anchor" href="#_1-1-概述" aria-label="Permalink to &quot;1.1 概述&quot;">​</a></h2><ul><li><p>根据<code>变量</code>中<code>存储</code>的<code>值</code>的<code>不同</code>，我们可以将<code>变量</code>分为两类：</p><ul><li><code>普通变量</code>：变量所对应的内存中存储的是<code>普通值</code>。</li><li><code>指针变量</code>：变量所对应的内存中存储的是<code>另一个变量的地址</code>。</li></ul></li><li><p>如下图所示：</p></li></ul><p><img src="/c/assets/1.L8V3GBrc.png" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>普通变量和指针变量的相同点：</p><ul><li>普通变量有内存空间，指针变量也有内存空间。</li><li>普通变量有内存地址，指针变量也有内存地址。</li><li>普通变量所对应的内存空间中有值，指针变量所对应的内存空间中也有值。</li></ul><p>普通变量和指针变量的不同点：</p><ul><li>普通变量所对应的内存空间存储的是普通的值，如：整数、小数、字符等；指针变量所对应的内存空间存储的是另外一个变量的地址。</li><li>普通变量有普通变量的运算方式，而指针变量有指针变量的运算方式（后续讲解）。</li></ul></div><ul><li>那么，在 C 语言中变量的数据类型就可以这么划分，如下所示：</li></ul><p><img src="/c/assets/2.BkF1yWLn.png" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>根据<code>普通变量</code>中<code>存储</code>的<code>值</code>的类型不同，可以将<code>普通变量类型</code>划分为<code>基本数据类型</code>（整型、字符类型、浮点类型、布尔类型）和<code>复合数据类型</code>（数组类型、结构体类型、共用体类型、枚举类型）。</li><li>根据<code>指针变量</code>所<code>指向空间</code>中<code>存储</code>的<code>值</code>的类型不同，可以将<code>指针类型</code>分为<code>基本数据类型指针</code>、<code>复合数据类型指针</code>、<code>函数指针</code>、<code>数组指针</code>等，例如：如果指针所指向的空间保存的是 int 类型，那么该指针就是 int 类型的指针。</li></ul></div><h2 id="_1-2-整数类型" tabindex="-1">1.2 整数类型 <a class="header-anchor" href="#_1-2-整数类型" aria-label="Permalink to &quot;1.2 整数类型&quot;">​</a></h2><h3 id="_1-2-1-概述" tabindex="-1">1.2.1 概述 <a class="header-anchor" href="#_1-2-1-概述" aria-label="Permalink to &quot;1.2.1 概述&quot;">​</a></h3><ul><li>整数类型简称整型，用于存储整数值，如：12、20、50 等。</li><li>根据所占<code>内存空间</code>大小的不同，可以将整数类型划分为：</li><li>① 短整型：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间（内存空间）</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned short （无符号短整型）</td><td>2 字节</td><td>0 ~ 65,535 (2^16 - 1)</td></tr><tr><td>[signed] short（有符号短整型，默认）</td><td>2 字节</td><td>-32,768 (- 2^15) ~ 32,767 (2^15 -1)</td></tr></tbody></table><ul><li>② 整型：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间（内存空间）</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned int（无符号整型）</td><td>4 字节（通常）</td><td>0 ~ 4294967295 (0 ~2^32 -1)</td></tr><tr><td>[signed] int（有符号整型，默认）</td><td>4 字节（通常）</td><td>-2147483648（- 2^31） ~ 2147483647 (2^31-1)</td></tr></tbody></table><ul><li>③ 长整型：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间（内存空间）</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned long（无符号长整型）</td><td>4 字节（通常）</td><td>0 ~2^32 -1</td></tr><tr><td>[signed] long（有符号长整型，默认）</td><td>4 字节（通常）</td><td>- 2^31 ~ 2^31-1</td></tr></tbody></table><ul><li>④ 长长整型：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间（内存空间）</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned long long（无符号长整型）</td><td>8 字节（通常）</td><td>0 ~2^64 -1</td></tr><tr><td>[signed] long long（有符号长整型，默认）</td><td>8 字节（通常）</td><td>- 2^63 ~ 2^63-1</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① C 语言默认没有规定各种数据类型所占存储单元的长度，但是通常需要遵守：<code>sizeof(short int) ≤ sizeof(int) ≤ sizeof(long int) ≤ sizeof(long long)</code> ，具体的存储空间由编译系统自行决定；其中，sizeof 是测量类型或变量、常量长度的运算符。</li><li>② short 至少 2 个字节，long 至少 4 个字节。</li><li>③ 之所以这么规定，是为了可以让 C 语言长久使用，因为目前主流的 CPU 都是 64 位，但是在 C语言刚刚出现的时候，CPU 还是以 8 位和 16 位为主。如果当时就将整型定死为 8 位或 16 位，那么现在我们肯定不会再学习 C 语言了。</li><li>④ 整型分为有符号 signed 和无符号 unsigned 两种，默认是 signed。</li><li>⑤ 在实际开发中，<code>最常用整型</code>就是 <code>int</code> 类型了，如果取值范围不够，就使用 long 或 long long 。</li><li>⑥ C 语言中的<code>格式占位符</code>非常多，只需要大致了解即可；因为，我们在实际开发中，一般都会使用 C++ 或 Rust 以及其它的高级编程语言，如：Java 等，早已经解决了需要通过<code>格式占位符</code>来输入和输出变量。</li></ul></div><h3 id="_1-2-2-短整型-了解" tabindex="-1">1.2.2 短整型（了解） <a class="header-anchor" href="#_1-2-2-短整型-了解" aria-label="Permalink to &quot;1.2.2 短整型（了解）&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 无符号短整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 有符号短整型</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 有符号表示的是正数、负数和 0 ，即有正负号。无符号表示的是 0 和正数，即正整数，没有符号。</li><li>② 在 <code>printf</code> 中<code>无符号短整型（unsigned short）</code>的<code>格式占位符</code>是 <code>%hu</code> ，<code>有符号短整型（signed short）</code>的<code>格式占位符</code>是 <code>%hd</code> 。</li><li>③ 可以通过 <code>sizeof</code> 运算符获取<code>无符号短整型（unsigned short）</code> 和 <code>有符号短整型（signed short）</code> 的<code>存储空间（所占内存空间）</code>。</li><li>③ 可以通过 <code>#include &lt;limits.h&gt;</code> 来获取 <code>无符号短整型（unsigned short）</code> 和<code>有符号短整型（signed short）</code>的<code>取值范围</code>。</li></ul></div><ul><li>示例：定义和打印短整型变量</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
@ -38,7 +38,7 @@
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;s3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hd</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // s3 = -200</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取存储空间</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取类型占用的内存大小（存储空间）</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
@ -52,7 +52,7 @@
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;short 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 2</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取类型的取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
@ -79,7 +79,7 @@
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i3 = -200</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取存储空间</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取类型占用的内存大小（存储空间）</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
@ -93,7 +93,7 @@
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;int 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取类型的取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
@ -120,7 +120,7 @@
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;l3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%ld</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // l3 = -200</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取存储空间</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取类型占用的内存大小（存储空间）</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
@ -134,7 +134,7 @@
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;long 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取类型的取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
@ -161,7 +161,7 @@
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;ll3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lld</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // ll3 = -200</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取存储空间</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><ul><li>示例：获取类型占用的内存大小（存储空间）</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
@ -175,7 +175,7 @@
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;long long 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 8</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：获取类型的取值范围</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
@ -207,7 +207,7 @@
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num6 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%llu\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num6);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num6 = 100</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br></div></div><h3 id="_1-2-7-精确宽度类型" tabindex="-1">1.2.7 精确宽度类型 <a class="header-anchor" href="#_1-2-7-精确宽度类型" aria-label="Permalink to &quot;1.2.7 精确宽度类型&quot;">​</a></h3><ul><li>在前文，我们了解到 C 语言的整数类型（short 、int、long、long long）在不同计算机上，占用的字节宽度可能不一样。但是，有的时候，我们希望整数类型的存储空间（字节宽度）是精确的，即：在任意平台（计算机）上都能一致，以提高程序的可移植性。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>Java 语言中的数据类型的存储空间（字节宽度）是一致的，这也是 Java 语言能够跨平台的重要原因之一（最主要的原因还是 JVM）。</li><li>在嵌入式开发中，使用精确宽度类型可以确保代码在各个平台上的一致性。</li></ul></div><ul><li>在 C 语言的标准头文件 <code>&lt;stdint.h&gt;</code> 中定义了一些新的类型别名，如下所示：</li></ul><table tabindex="0"><thead><tr><th>类型名称</th><th>含义</th></tr></thead><tbody><tr><td>int8_t</td><td>8 位有符号整数</td></tr><tr><td>int16_t</td><td>16 位有符号整数</td></tr><tr><td>int32_t</td><td>32 位有符号整数</td></tr><tr><td>int64_t</td><td>64 位有符号整数</td></tr><tr><td>uint8_t</td><td>8 位无符号整数</td></tr><tr><td>uint16_t</td><td>16 位无符号整数</td></tr><tr><td>uint32_t</td><td>32 位无符号整数</td></tr><tr><td>uint64_t64</td><td>64 位无符号整数</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>上面的这些类型都是类型别名，编译器会指定它们指向的底层类型，如：在某个系统中，如果 int 类型是 32 位，那么 int32_t 就会指向 int ；如果 long 类型是 32 位，那么 int32_t 就会指向 long。</p></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br></div></div><h3 id="_1-2-7-精确宽度类型" tabindex="-1">1.2.7 精确宽度类型 <a class="header-anchor" href="#_1-2-7-精确宽度类型" aria-label="Permalink to &quot;1.2.7 精确宽度类型&quot;">​</a></h3><ul><li>在前文，我们了解到 C 语言的整数类型（short 、int、long、long long）在不同计算机上，占用的字节宽度可能不一样。但是，有的时候，我们希望整数类型的存储空间（字节宽度）是精确的，即：在任意平台（计算机）上都能一致，以提高程序的可移植性。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>Java 语言中的数据类型的存储空间（字节宽度）是一致的，这也是 Java 语言能够跨平台的原因之一（最主要的原因还是 JVM）。</li><li>在嵌入式开发中，使用精确宽度类型可以确保代码在各个平台上的一致性。</li></ul></div><ul><li>在 C 语言的标准头文件 <code>&lt;stdint.h&gt;</code> 中定义了一些新的类型别名，如下所示：</li></ul><table tabindex="0"><thead><tr><th>类型名称</th><th>含义</th></tr></thead><tbody><tr><td>int8_t</td><td>8 位有符号整数</td></tr><tr><td>int16_t</td><td>16 位有符号整数</td></tr><tr><td>int32_t</td><td>32 位有符号整数</td></tr><tr><td>int64_t</td><td>64 位有符号整数</td></tr><tr><td>uint8_t</td><td>8 位无符号整数</td></tr><tr><td>uint16_t</td><td>16 位无符号整数</td></tr><tr><td>uint32_t</td><td>32 位无符号整数</td></tr><tr><td>uint64_t</td><td>64 位无符号整数</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>上面的这些类型都是类型别名，编译器会指定它们指向的底层类型，如：在某个系统中，如果 int 类型是 32 位，那么 int32_t 就会指向 int ；如果 long 类型是 32 位，那么 int32_t 就会指向 long。</p></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdint.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
@ -249,7 +249,7 @@
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><h3 id="_1-2-9-数值溢出" tabindex="-1">1.2.9 数值溢出 <a class="header-anchor" href="#_1-2-9-数值溢出" aria-label="Permalink to &quot;1.2.9 数值溢出&quot;">​</a></h3><ul><li><p>所谓的数值溢出指的是：当超过一个数据类型能够存放的最大范围的时候，数值就会溢出。</p><ul><li>如果达到了最⼤值，再进行加法计算，数据就会超过该类型能够表示的最大值，叫做上溢出。</li><li>如果这个数⽬前是最小值，再进行减法计算， 数据就会超过该类型的最小值， 叫做下溢出。</li></ul></li><li><p>在 C 语言中，<code>整数</code>的<code>数据类型</code>分为<code>无符号</code>和<code>有符号</code>的，其在底层表示和存储是不一样的，即：</p><ul><li>无符号整数不使用最高位作为符号位，所有的位都用于表示数值，如：对于一个 4 位无符号整数，二进制表示的范围是从 0000 到 1111 ，那么十进制表示的范围是从 0 到 15。</li><li>有符号整数使用最高位作为符号位，这意味着它们可以表示正数和负数，通常使用补码来表示有符号整数。在补码表示法中：最高位为 0 表示正数、最高位为 1 表示负数，如：对于一个4位有符号整数，二进制表示的范围是从 0000（0） 到 0111 （7），1000 （-8）到 1111（-1）。</li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>在 C 语言中，无符号整数，最高位不是符号位，它只是数值的一部分。</li><li>在 C 语言中，有符号整数，最高位是符号位，用于表示正负数。</li></ul></div><ul><li><p>对于无符号的数值溢出：</p><ul><li>当数据到达最大值的时候，再加 1 就会回到无符号数的最小值。</li><li>当数据达到最小值的时候，再减 1 就会回到无符号数的最大值。</li></ul></li><li><p>那么，无符号的上溢出，原理就是这样的：</p></li></ul><p><img src="/c/assets/3.CceY8r_n.png" alt=""></p><ul><li>那么，无符号的下溢，原理就是这样的（需要先借位，然后再减）：</li></ul><p><img src="/c/assets/4.DHaUgOwj.png" alt=""></p><ul><li><p>对于有符号的数值溢出：</p><ul><li>当数据到达最大值的时候，再加 1 就会回到有符号数的最小值。</li><li>当数据达到最小值的时候，再减 1 就会回到有符号数的最大值。</li></ul></li><li><p>那么，有符号的上溢出，原理就是这样的：</p></li></ul><p><img src="/c/assets/5.CXGaq_zh.png" alt=""></p><ul><li>那么，有符号的下溢出，原理就是这样的：</li></ul><p><img src="/c/assets/6.BrZYAEEl.png" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>在实际开发中，选择合适的数据类型，以避免数值溢出问题！！！</p></div><ul><li>示例：无符号的上溢出和下溢出</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><h3 id="_1-2-9-数值溢出" tabindex="-1">1.2.9 数值溢出 <a class="header-anchor" href="#_1-2-9-数值溢出" aria-label="Permalink to &quot;1.2.9 数值溢出&quot;">​</a></h3><ul><li><p>所谓的数值溢出指的是：当超过一个数据类型能够存放的最大范围的时候，数值就会溢出。</p><ul><li>如果达到了最大值，再进行加法计算，数据就会超过该类型能够表示的最大值，叫做上溢出。</li><li>如果这个数目前是最小值，再进行减法计算， 数据就会超过该类型的最小值， 叫做下溢出。</li></ul></li><li><p>在 C 语言中，<code>整数</code>的<code>数据类型</code>分为<code>无符号</code>和<code>有符号</code>的，其在底层表示和存储是不一样的，即：</p><ul><li><code>无符号整数不使用最高位作为符号位</code>，所有的位都用于表示数值，如：对于一个 4 位无符号整数，二进制表示的范围是从 0000 到 1111 ，那么十进制表示的范围是从 0 到 15。</li><li><code>有符号整数使用最高位作为符号位</code>，这意味着它们可以表示正数和负数，通常使用补码来表示有符号整数。在补码表示法中：最高位为 0 表示正数、最高位为 1 表示负数，如：对于一个4位有符号整数，二进制表示的范围是从 0000（0） 到 0111 （7），1000 （-8）到 1111（-1）。</li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>在 C 语言中，无符号整数，最高位不是符号位，它是数值的一部分。</li><li>在 C 语言中，有符号整数，最高位是符号位，用于表示正负数。</li></ul></div><ul><li><p>对于无符号的数值溢出：</p><ul><li>当数据到达最大值的时候，再加 1 就会回到无符号数的最小值。</li><li>当数据达到最小值的时候，再减 1 就会回到无符号数的最大值。</li></ul></li><li><p>那么，无符号的上溢出，原理就是这样的：</p></li></ul><p><img src="/c/assets/3.CceY8r_n.png" alt=""></p><ul><li>那么，无符号的下溢出，原理就是这样的（需要先借位，然后再减）：</li></ul><p><img src="/c/assets/4.DHaUgOwj.png" alt=""></p><ul><li><p>对于有符号的数值溢出：</p><ul><li>当数据到达最大值的时候，再加 1 就会回到有符号数的最小值。</li><li>当数据达到最小值的时候，再减 1 就会回到有符号数的最大值。</li></ul></li><li><p>那么，有符号的上溢出，原理就是这样的：</p></li></ul><p><img src="/c/assets/5.CXGaq_zh.png" alt=""></p><ul><li>那么，有符号的下溢出，原理就是这样的：</li></ul><p><img src="/c/assets/6.BrZYAEEl.png" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>在实际开发中，选择合适的数据类型，以避免数值溢出问题！！！</p></div><ul><li>示例：无符号的上溢出和下溢出</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
@ -273,8 +273,523 @@
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;有符号的下溢出 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%hd</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 32767</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><h2 id="_1-3-浮点类型" tabindex="-1">1.3 浮点类型 <a class="header-anchor" href="#_1-3-浮点类型" aria-label="Permalink to &quot;1.3 浮点类型&quot;">​</a></h2><h2 id="_1-4-字符类型" tabindex="-1">1.4 字符类型 <a class="header-anchor" href="#_1-4-字符类型" aria-label="Permalink to &quot;1.4 字符类型&quot;">​</a></h2><h2 id="_1-5-布尔类型" tabindex="-1">1.5 布尔类型 <a class="header-anchor" href="#_1-5-布尔类型" aria-label="Permalink to &quot;1.5 布尔类型&quot;">​</a></h2><h2 id="_1-6-数据类型转换" tabindex="-1">1.6 数据类型转换 <a class="header-anchor" href="#_1-6-数据类型转换" aria-label="Permalink to &quot;1.6 数据类型转换&quot;">​</a></h2><h1 id="第二章-运算符" tabindex="-1">第二章：运算符 <a class="header-anchor" href="#第二章-运算符" aria-label="Permalink to &quot;第二章：运算符&quot;">​</a></h1><h2 id="_2-1-概述" tabindex="-1">2.1 概述 <a class="header-anchor" href="#_2-1-概述" aria-label="Permalink to &quot;2.1 概述&quot;">​</a></h2><h2 id="_2-2-算术运算符" tabindex="-1">2.2 算术运算符 <a class="header-anchor" href="#_2-2-算术运算符" aria-label="Permalink to &quot;2.2 算术运算符&quot;">​</a></h2><h2 id="_2-3-关系运算符-比较运算符" tabindex="-1">2.3 关系运算符（比较运算符） <a class="header-anchor" href="#_2-3-关系运算符-比较运算符" aria-label="Permalink to &quot;2.3 关系运算符（比较运算符）&quot;">​</a></h2><h2 id="_2-4-逻辑运算符" tabindex="-1">2.4 逻辑运算符 <a class="header-anchor" href="#_2-4-逻辑运算符" aria-label="Permalink to &quot;2.4 逻辑运算符&quot;">​</a></h2><h2 id="_2-5-位运算符" tabindex="-1">2.5 位运算符 <a class="header-anchor" href="#_2-5-位运算符" aria-label="Permalink to &quot;2.5 位运算符&quot;">​</a></h2><h2 id="_2-6-三元运算符" tabindex="-1">2.6 三元运算符 <a class="header-anchor" href="#_2-6-三元运算符" aria-label="Permalink to &quot;2.6 三元运算符&quot;">​</a></h2><h2 id="_2-7-运算符优先级" tabindex="-1">2.7 运算符优先级 <a class="header-anchor" href="#_2-7-运算符优先级" aria-label="Permalink to &quot;2.7 运算符优先级&quot;">​</a></h2></div></div></main><footer class="VPDocFooter" data-v-39a288b8 data-v-d4a0bba5><!--[--><!--]--><div class="edit-info" data-v-d4a0bba5><!----><div class="last-updated" data-v-d4a0bba5><p class="VPLastUpdated" data-v-d4a0bba5 data-v-7e05ebdb>上次更新: <time datetime="2024-07-17T09:21:51.000Z" data-v-7e05ebdb></time></p></div></div><nav class="prev-next" aria-labelledby="doc-footer-aria-label" data-v-d4a0bba5><span class="visually-hidden" id="doc-footer-aria-label" data-v-d4a0bba5>Pager</span><div class="pager" data-v-d4a0bba5><a class="VPLink link pager-link prev" href="/c/notes/01_c-basic/02_xdx/" data-v-d4a0bba5><!--[--><span class="desc" data-v-d4a0bba5>上一篇</span><span class="title" data-v-d4a0bba5>变量和进制</span><!--]--></a></div><div class="pager" data-v-d4a0bba5><!----></div></nav></footer><!--[--><!--]--></div></div></div><!--[--><!--]--></div></div><footer class="VPFooter has-sidebar" data-v-5d98c3a5 data-v-e315a0ad><div class="container" data-v-e315a0ad><p class="message" data-v-e315a0ad>Released under the MIT License.</p><p class="copyright" data-v-e315a0ad>Copyright © 2024 许大仙</p></div></footer><!--[--><!--]--></div></div>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><h2 id="_1-3-浮点类型" tabindex="-1">1.3 浮点类型 <a class="header-anchor" href="#_1-3-浮点类型" aria-label="Permalink to &quot;1.3 浮点类型&quot;">​</a></h2><h3 id="_1-3-1-概述" tabindex="-1">1.3.1 概述 <a class="header-anchor" href="#_1-3-1-概述" aria-label="Permalink to &quot;1.3.1 概述&quot;">​</a></h3><ul><li>在生活中，我们除了使用<code>整数</code>，如：18、25 之外，还会使用到<code>小数</code>，如：3.1415926、6.18 等，<code>小数</code>在计算机中也被称为<code>浮点数</code>（和底层存储有关）。</li><li><code>整数</code>在计算机底层的存储被称为<code>定点存储</code>，如下所示：</li></ul><p><img src="/c/assets/7.DpCroFHv.png" alt=""></p><ul><li><code>小数</code>在计算机底层的存储被称为<code>浮点存储</code>，如下所示：</li></ul><p><img src="/c/assets/8.Cr7P0Gji.png" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 计算机底层就是采取类似科学计数法的形式来存储小数的，而科学技术法的表现就是这样的，如：3.12 * 10^-2 ；其中，10 是基数，-2 是指数，而 3.12 是尾数。</li><li>② 因为尾数区的内存空间的宽度不同，导致了小数的精度也不相同，所以小数在计算机中也称为浮点数。</li></ul></div><ul><li>在 C 语言中，变量的浮点类型，如下所示：</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储大小</th><th>值的范围</th><th>有效小数位数</th></tr></thead><tbody><tr><td>float（单精度）</td><td>4 字节</td><td>1.2E-38 ~ 3.4E+38</td><td>6 ~ 9</td></tr><tr><td>double（双精度）</td><td>8 字节</td><td>2.3E-308 ~ 1.7E+308</td><td>15 ~ 18</td></tr><tr><td>long double（长双精度）</td><td>16 字节</td><td>3.4E-4932 ~ 1.2E+4932</td><td>18 或更多</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 各类型的存储大小和精度受到操作系统、编译器、硬件平台的影响。</li><li>② 浮点型数据有两种表现形式： <ul><li>十进制数形式：3.12、512.0f、0.512（.512，可以省略 0 ）</li><li>科学计数法形式：5.12e2（e 表示基数 10）、5.12E-2（E 表示基数 10）。</li></ul></li><li>③ 在实际开发中，对于浮点类型，建议使用 double 类型；如果范围不够，就使用 long double 类型。</li></ul></div><h3 id="_1-3-2-格式占位符" tabindex="-1">1.3.2 格式占位符 <a class="header-anchor" href="#_1-3-2-格式占位符" aria-label="Permalink to &quot;1.3.2 格式占位符&quot;">​</a></h3><ul><li><p>对于 float 类型的格式占位符，是 <code>%f</code> ，默认会保留 <code>6</code> 位小数；可以指定小数位，如：<code>%.2f</code> 表示保留 <code>2</code> 位小数。</p></li><li><p>对于 double 类型的格式占位符，是 <code>%lf</code> ，默认会保留 <code>6</code> 位小数；可以指定小数位，如：<code>%.2lf</code> 表示保留 <code>2</code> 位小数。</p></li><li><p>对于 long double 类型的格式占位符，是 <code>%Lf</code> ，默认会保留 <code>6</code> 位小数；可以指定小数位，如：<code>%.2Lf</code> 表示保留 <code>2</code> 位小数。</p></li><li><p>如果想输出<code>科学计数法</code>形式的浮点数，则使用 <code>%e</code>。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> float</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> f1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10.0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;f1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%f</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, f1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // f1 = 10.000000</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;f1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2f</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, f1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // f1 = 10.00</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 13.14159265354</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lf</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1 = 13.141593</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2lf</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1 = 13.14</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 13.14159265354</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%LF</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1 = 13.141593</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2LF</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1 = 13.14</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> float</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> f1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3.1415926</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3.14</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">e</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;f1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2f</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, f1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // f1 = 3.14</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;f1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2e</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, f1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // f1 = 3.14e+00</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2lf</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d2 = 314.00</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2e</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d2 = 3.14e+02</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br></div></div><h3 id="_1-3-3-字面量后缀" tabindex="-1">1.3.3 字面量后缀 <a class="header-anchor" href="#_1-3-3-字面量后缀" aria-label="Permalink to &quot;1.3.3 字面量后缀&quot;">​</a></h3><ul><li><p>浮点数字面量默认是 double 类型。</p></li><li><p>如果需要表示 float 类型的字面量，需要后面添加后缀 f 或 F。</p></li><li><p>如果需要表示 long double 类型的字面量，需要后面添加后缀 l 或 L。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> float</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> f1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3.1415926</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">f</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3.1415926</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3.1415926</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">L</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;f1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2f</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, f1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // f1 = 3.14</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.3lf</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d2 = 3.142</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.4Lf</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d3 = 3.1416</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br></div></div><h3 id="_1-3-4-类型占用的内存大小-存储空间" tabindex="-1">1.3.4 类型占用的内存大小（存储空间） <a class="header-anchor" href="#_1-3-4-类型占用的内存大小-存储空间" aria-label="Permalink to &quot;1.3.4 类型占用的内存大小（存储空间）&quot;">​</a></h3><ul><li><p>可以通过 sizeof 运算符来获取 float、double 以及 long double 类型占用的内存大小（存储空间）。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;float 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">float</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">));</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;double 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">));</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 8</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;long double 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%zu</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">));</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 16</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><h3 id="_1-3-5-类型的取值范围" tabindex="-1">1.3.5 类型的取值范围 <a class="header-anchor" href="#_1-3-5-类型的取值范围" aria-label="Permalink to &quot;1.3.5 类型的取值范围&quot;">​</a></h3><ul><li><p>可以通过 <code>#include &lt;float.h&gt;</code> 来获取类型的取值范围。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;float.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;float 的取值范围是：[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.38f</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%f</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">] </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, FLT_MIN, FLT_MAX);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;double 的取值范围是：[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lf</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lf</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">] </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, DBL_MIN, DBL_MAX);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;double 的取值范围是：[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%Lf</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%Lf</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">] </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, LDBL_MIN, LDBL_MAX);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><h2 id="_1-4-字符类型" tabindex="-1">1.4 字符类型 <a class="header-anchor" href="#_1-4-字符类型" aria-label="Permalink to &quot;1.4 字符类型&quot;">​</a></h2><h3 id="_1-4-1-概述" tabindex="-1">1.4.1 概述 <a class="header-anchor" href="#_1-4-1-概述" aria-label="Permalink to &quot;1.4.1 概述&quot;">​</a></h3><ul><li>在生活中，我们会经常说：今天天气真 <code>好</code>，我的性别是 <code>女</code>，我今年 <code>10</code> 岁，像这类数据，在 C 语言中就可以用字符（char）来表示。</li><li>在 C 语言中，变量的<code>字符类型</code>可以表示<code>单</code>个字符，如：<code>&#39;1&#39;</code>、<code>&#39;A&#39;</code>、<code>&#39;&amp;&#39;</code>。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>C 语言的出现在 1972 年，由美国人丹尼斯·里奇设计出来；那个时候，只需要 1 个字节的内存空间，就可以完美的表示拉丁体系（英文）文字，如：a-z、A-Z、0-9 以及一些特殊符号；所以，C 语言中不支持多个字节的字符，如：中文、日文等。</li><li>C 语言中没有字符串类型，是使用字符数组（char 数组）来模拟字符串的，并且字符数组也不是字符串，而是构造类型。</li><li>在 C 语言中，如果想要输出中文、日文等多字节字符，就需要使用字符数组（char 数组）。</li><li>在 C++、Java 等高级编程语言中，已经提供了 String （字符串）类型，原生支持 Unicode，可以方便地处理多语言和特殊字符。</li></ul></div><ul><li>在 C 语言中，可以使用<code>转义字符 \</code>来表示特殊含义的字符。</li></ul><table tabindex="0"><thead><tr><th><strong>转义字符</strong></th><th><strong>说明</strong></th></tr></thead><tbody><tr><td><code>\b</code></td><td>退格</td></tr><tr><td><code>\n</code></td><td>换行符</td></tr><tr><td><code>\r</code></td><td>回车符</td></tr><tr><td><code>\t</code></td><td>制表符</td></tr><tr><td><code>\&quot;</code></td><td>双引号</td></tr><tr><td><code>\&#39;</code></td><td>单引号</td></tr><tr><td><code>\\</code></td><td>反斜杠</td></tr><tr><td>...</td><td></td></tr></tbody></table><h3 id="_1-4-2-格式占位符" tabindex="-1">1.4.2 格式占位符 <a class="header-anchor" href="#_1-4-2-格式占位符" aria-label="Permalink to &quot;1.4.2 格式占位符&quot;">​</a></h3><ul><li><p>在 C 语言中，使用 <code>%c</code> 来表示 char 类型。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;&amp;&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;c = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, c);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // c = &amp;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;a&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;c2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, c2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // c2 = a</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;A&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;c3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, c3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // c3 = A</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br></div></div><h3 id="_1-4-3-类型占用的内存大小-存储空间" tabindex="-1">1.4.3 类型占用的内存大小（存储空间） <a class="header-anchor" href="#_1-4-3-类型占用的内存大小-存储空间" aria-label="Permalink to &quot;1.4.3 类型占用的内存大小（存储空间）&quot;">​</a></h3><ul><li><p>可以通过 sizeof 运算符来获取 char 类型占用的内存大小（存储空间）。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;char 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">));</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 1 </span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned char 的存储空间是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 字节</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">));</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 1</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br></div></div><h3 id="_1-4-4-类型的取值范围" tabindex="-1">1.4.4 类型的取值范围 <a class="header-anchor" href="#_1-4-4-类型的取值范围" aria-label="Permalink to &quot;1.4.4 类型的取值范围&quot;">​</a></h3><ul><li><p>可以通过 <code>#include &lt;limits.h&gt;</code> 来获取类型的取值范围。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;char 范围是[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">] </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, CHAR_MIN,CHAR_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [-128,127]</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;unsigned char 范围是[0,</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">]</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, UCHAR_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [0,255]</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><h3 id="_1-4-3-字符类型的本质" tabindex="-1">1.4.3 字符类型的本质 <a class="header-anchor" href="#_1-4-3-字符类型的本质" aria-label="Permalink to &quot;1.4.3 字符类型的本质&quot;">​</a></h3><ul><li>在 C 语言中，char 本质上就是一个整数，是 ASCII 码中对应的数字，占用的内存大小是 1 个字节（存储空间），所以 char 类型也可以进行数学运算。</li></ul><p><img src="/c/assets/9.NlBmD7pA.png" alt=""></p><ul><li>char 类型同样分为 signed char（无符号）和 unsigned char（有符号），其中 signed char 取值范围-128 ~ 127，unsigned char取值范围 0 ~ 255，默认是否带符号取决于当前运行环境。</li><li><code>字符类型的数据</code>在计算机中<code>存储</code>和<code>读取</code>的过程，如下所示：</li></ul><p><img src="/c/assets/10.ZiBq6Pno.png" alt=""></p><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;limits.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // char 类型字面量需要使用单引号包裹</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;A&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;9&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\t</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;c1=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, c3=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, c2=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a1, a3, a2);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // char 类型本质上整数可以进行运算</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;b&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 101</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">-&gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, b1, b1);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">-&gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, b2, b2);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">+</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, b1, b2, b1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b2);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // char 类型取值范围</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 200</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 无符号 char 取值范围 0 ~255</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 200</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 有符号 char 取值范围 -128~127，c2会超出范围</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 200</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 当前系统，char 默认是 signed char</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;c1=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, c2=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, c3=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, c1, c2, c3);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br></div></div><h2 id="_1-5-布尔类型" tabindex="-1">1.5 布尔类型 <a class="header-anchor" href="#_1-5-布尔类型" aria-label="Permalink to &quot;1.5 布尔类型&quot;">​</a></h2><h3 id="_1-5-1-概述" tabindex="-1">1.5.1 概述 <a class="header-anchor" href="#_1-5-1-概述" aria-label="Permalink to &quot;1.5.1 概述&quot;">​</a></h3><ul><li>布尔值用于表示 true（真）、false（假）两种状态，通常用于逻辑运算和条件判断。</li></ul><h3 id="_1-5-2-早期的布尔类型" tabindex="-1">1.5.2 早期的布尔类型 <a class="header-anchor" href="#_1-5-2-早期的布尔类型" aria-label="Permalink to &quot;1.5.2 早期的布尔类型&quot;">​</a></h3><ul><li><p>在 C 语言标准（C89）中，并没有为布尔值单独设置一个数据类型，所以在判断真、假的时候，使用 <code>0</code> 表示 <code>false</code>（假），<code>非 0</code> 表示 <code>true</code>（真）。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> </span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 使用整型来表示真和假两种状态</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> handsome </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">; </span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;帅不帅[0 丑，1 帅]： &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">handsome);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (handsome) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很帅！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很丑！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h3 id="_1-5-3-宏定义的布尔类型" tabindex="-1">1.5.3 宏定义的布尔类型 <a class="header-anchor" href="#_1-5-3-宏定义的布尔类型" aria-label="Permalink to &quot;1.5.3 宏定义的布尔类型&quot;">​</a></h3><ul><li><p>判断真假的时候，以 <code>0</code> 为 <code>false</code>（假）、<code>1</code> 为 <code>true</code>（真），并不直观；所以，我们可以借助 C 语言的宏定义。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">// 宏定义</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#define</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> BOOL</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#define</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> TRUE</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#define</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> FALSE</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> BOOL handsome </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;帅不帅[FALSE 丑，TRUE 帅]： &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">handsome);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (handsome) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很帅！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很丑！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br></div></div><h3 id="_1-5-4-c99-标准中的布尔类型" tabindex="-1">1.5.4 C99 标准中的布尔类型 <a class="header-anchor" href="#_1-5-4-c99-标准中的布尔类型" aria-label="Permalink to &quot;1.5.4 C99 标准中的布尔类型&quot;">​</a></h3><ul><li><p>在 C99 中提供了 <code>_Bool</code> 关键字，用于表示布尔类型；其实，<code>_Bool</code>类型的值是整数类型的别名，和一般整型不同的是，<code>_Bool</code>类型的值只能赋值为 <code>0</code> 或 <code>1</code> （0 表示假、1 表示真），其它<code>非 0</code> 的值都会被存储为 <code>1</code> 。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> _Bool</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> handsome </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;帅不帅[0 丑，1 帅]： &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">handsome);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (handsome) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很帅！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很丑！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h3 id="_1-5-5-c99-标准头文件中的布尔类型-推荐" tabindex="-1">1.5.5 C99 标准头文件中的布尔类型（推荐） <a class="header-anchor" href="#_1-5-5-c99-标准头文件中的布尔类型-推荐" aria-label="Permalink to &quot;1.5.5 C99 标准头文件中的布尔类型（推荐）&quot;">​</a></h3><ul><li>在 C99 中提供了一个头文件 <code>&lt;stdbool.h&gt;</code>，定义了 <code>bool</code> 代表 <code>_Bool</code>，<code>false</code> 代表 <code>0</code> ，<code>true</code> 代表 <code>1</code> 。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>在 C++、Java 等高级编程语言中是有 boolean 类型的关键字的。</p></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> bool</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> handsome </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> false</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;帅不帅[false 丑，true 帅]： &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">handsome);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (handsome) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很帅！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你真的很丑！！！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h2 id="_1-6-数据类型转换" tabindex="-1">1.6 数据类型转换 <a class="header-anchor" href="#_1-6-数据类型转换" aria-label="Permalink to &quot;1.6 数据类型转换&quot;">​</a></h2><h3 id="_1-6-1-概述" tabindex="-1">1.6.1 概述 <a class="header-anchor" href="#_1-6-1-概述" aria-label="Permalink to &quot;1.6.1 概述&quot;">​</a></h3><ul><li>在 C 语言编程中，经常需要对不同类型的数据进行运算，运算前需要先转换为同一类型，再运算。为了解决数据类型不一致的问题，需要对数据的类型进行转换。</li></ul><h3 id="_1-6-2-自动类型转换-隐式转换" tabindex="-1">1.6.2 自动类型转换（隐式转换） <a class="header-anchor" href="#_1-6-2-自动类型转换-隐式转换" aria-label="Permalink to &quot;1.6.2 自动类型转换（隐式转换）&quot;">​</a></h3><h4 id="_1-6-2-1-运算过程中的自动类型转换" tabindex="-1">1.6.2.1 运算过程中的自动类型转换 <a class="header-anchor" href="#_1-6-2-1-运算过程中的自动类型转换" aria-label="Permalink to &quot;1.6.2.1 运算过程中的自动类型转换&quot;">​</a></h4><ul><li>不同类型的数据进行混合运算的时候，会发生数据类型转换，<code>窄类型会自动转换为宽类型</code>，这样就不会造成精度损失。</li></ul><p><img src="/c/assets/11.DAgmsf-w.png" alt=""></p><ul><li>转换规则： <ul><li>① 不同类型的整数进行运算的时候，窄类型整数会自动转换为宽类型整数。</li><li>② 不同类型的浮点数进行运算的时候，精度小的类型会自动转换为精度大的类型。</li><li>③ 整数和浮点数进行运算的时候，整数会自动转换为浮点数。</li></ul></li><li>转换方向：</li></ul><p><img src="/c/assets/12.B2iC37fw.png" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>最好避免无符号整数与有符号整数的混合运算，因为这时 C 语言会自动将 signed int 转为 unsigned int ，可能不会得到预期的结果。</p></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">/**</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> * 不同的整数类型混合运算时，宽度较小的类型会提升为宽度较大的类型，比如 short 转为 int ，int 转为 long 等。</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> */</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 20</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // s1 是 short 类型，i 是 int 类型，当 s1 和 i 运算的时候，会自动转为 int 类型后，然后再计算。</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> result </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;result = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, result);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 20</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // n2 是有符号，n3 是无符号，当 n2 和 n3 运算的时候，会自动转为无符号类型后，然后再计算。</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> result </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n3;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;result = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, result);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">/**</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">* 不同的浮点数类型混合运算时，宽度较小的类型转为宽度较大的类型，比如 float 转为 double ，double 转为 long double 。</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">*/</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> float</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> f1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1.25</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">f</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 4.58667435</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // f1 是 float 类型，d2 是 double 类型，当 f1 和 d2 运算的时候，会自动转为 double 类型后，然后再计算。</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> result </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> f1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d2;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;result = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.8lf</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, result);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">/**</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> * 整型与浮点型运算，整型转为浮点型</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> */</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n4 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1.67</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // n4 是 int 类型，d3 是 double 类型，当 n4 和 d3 运算的时候，会自动转为 double 类型后，然后再计算。</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> result </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n4 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d3;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2lf</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, result);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h4 id="_1-6-2-2-赋值时的自动类型转换" tabindex="-1">1.6.2.2 赋值时的自动类型转换 <a class="header-anchor" href="#_1-6-2-2-赋值时的自动类型转换" aria-label="Permalink to &quot;1.6.2.2 赋值时的自动类型转换&quot;">​</a></h4><ul><li>在赋值运算中，赋值号两边量的数据类型不同时，等号右边的类型将转换为左边的类型。</li><li>如果窄类型赋值给宽类型，不会造成精度损失；如果宽类型赋值给窄类型，会造成精度损失。</li></ul><p><img src="/c/assets/14.BlE3ZFud.png" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>C 语言在检查类型匹配方面不太严格，最好不要养成这样的习惯。</p></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 赋值：窄类型赋值给宽类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a1;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a2: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2f\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a2: 10.00</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 转换：将宽类型转换为窄类型</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10.5</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b1;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;b2: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, b2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // b2: 10</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br></div></div><h3 id="_1-6-3-强制类型转换" tabindex="-1">1.6.3 强制类型转换 <a class="header-anchor" href="#_1-6-3-强制类型转换" aria-label="Permalink to &quot;1.6.3 强制类型转换&quot;">​</a></h3><ul><li>隐式类型转换中的宽类型赋值给窄类型，编译器是会产生警告的，提示程序存在潜在的隐患，如果非常明确地希望转换数据类型，就需要用到强制（或显式）类型转换。</li><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">数据类型 变量名 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (类型名)变量、常量或表达式;</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>强制类型转换会导致精度损失！！！</p></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(){</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1.934</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 4.2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)d1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)d2;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1 转为 1，d2 转为 4，结果是 5</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)(d1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1+d2 = 6.134，6.134 转为 6</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">3.5</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> *</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> +</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 6</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> *</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1.5</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 35.0 + 9.0 = 44.0 -&gt; int = 44</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num1=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num1);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num2=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num2);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;num3=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num3);</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><h1 id="第二章-运算符-⭐" tabindex="-1">第二章：运算符（⭐） <a class="header-anchor" href="#第二章-运算符-⭐" aria-label="Permalink to &quot;第二章：运算符（⭐）&quot;">​</a></h1><h2 id="_2-1-概述" tabindex="-1">2.1 概述 <a class="header-anchor" href="#_2-1-概述" aria-label="Permalink to &quot;2.1 概述&quot;">​</a></h2><ul><li>运算符是一种特殊的符号，用于数据的运算、赋值和比较等。</li><li><code>表达式</code>指的是一组运算数、运算符的组合，表达式<code>一定具有值</code>，一个变量或一个常量可以是表达式，变量、常量和运算符也可以组成表达式，如：</li></ul><p><img src="/c/assets/15.CdvhiwcU.png" alt=""></p><ul><li><code>操作数</code>指的是<code>参与运算</code>的<code>值</code>或者<code>对象</code>，如：</li></ul><p><img src="/c/assets/16.D74t3-Xt.png" alt=""></p><ul><li>根据<code>操作数</code>的<code>个数</code>，可以将运算符分为： <ul><li>一元运算符（一目运算符）。</li><li>二元运算符（二目运算符）。</li><li>三元运算符（三目运算符）。</li></ul></li><li>根据<code>功能</code>，可以将运算符分为： <ul><li>算术运算符。</li><li>关系运算符（比较运算符）。</li><li>逻辑运算符。</li><li>赋值运算符。</li><li>逻辑运算符。</li><li>位运算符。</li><li>三元运算符。</li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>掌握一个运算符，需要关注以下几个方面：</p><ul><li>① 运算符的含义。</li><li>② 运算符操作数的个数。</li><li>③ 运算符所组成的表达式。</li><li>④ 运算符有无副作用，即：运算后是否会修改操作数的值。</li></ul></div><h2 id="_2-2-算术运算符" tabindex="-1">2.2 算术运算符 <a class="header-anchor" href="#_2-2-算术运算符" aria-label="Permalink to &quot;2.2 算术运算符&quot;">​</a></h2><ul><li>算术运算符是对数值类型的变量进行运算的，如下所示：</li></ul><table tabindex="0"><thead><tr><th>运算符</th><th>描述</th><th>操作数个数</th><th>组成的表达式的值</th><th>副作用</th></tr></thead><tbody><tr><td><code>+</code></td><td>正号</td><td>1</td><td>操作数本身</td><td>❎</td></tr><tr><td><code>-</code></td><td>负号</td><td>1</td><td>操作数符号取反</td><td>❎</td></tr><tr><td><code>+</code></td><td>加号</td><td>2</td><td>两个操作数之和</td><td>❎</td></tr><tr><td><code>-</code></td><td>减号</td><td>2</td><td>两个操作数之差</td><td>❎</td></tr><tr><td><code>*</code></td><td>乘号</td><td>2</td><td>两个操作数之积</td><td>❎</td></tr><tr><td><code>/</code></td><td>除号</td><td>2</td><td>两个操作数之商</td><td>❎</td></tr><tr><td><code>%</code></td><td>取模（取余）</td><td>2</td><td>两个操作数相除的余数</td><td>❎</td></tr><tr><td><code>++</code></td><td>自增</td><td>1</td><td>操作数自增前或自增后的值</td><td>✅</td></tr><tr><td><code>--</code></td><td>自减</td><td>1</td><td>操作数自减前或自减后的值</td><td>✅</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>自增和自减：</p><ul><li>① 自增、自减运算符可以写在操作数的前面也可以写在操作数后面，不论前面还是后面，对操作数的副作用是一致的。</li><li>② 自增、自减运算符在前在后，对于表达式的值是不同的。 如果运算符在前，表达式的值是操作数自增、自减之后的值；如果运算符在后，表达式的值是操作数自增、自减之前的值。</li><li>③ <code>变量前++</code>：变量先自增 1 ，然后再运算；<code>变量后++</code>：变量先运算，然后再自增 1 。</li><li>④ <code>变量前--</code>：变量先自减 1 ，然后再运算；<code>变量后--</code>：变量先运算，然后再自减 1 。</li></ul></div><ul><li>示例：正号和负号</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 12</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">x, x2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> +</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">x;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> y </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">67</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> y1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">y, y2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> +</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">y;</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;x1=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, x2=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, x1, x2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // x1=-12, x2=12</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;y1=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">, y2=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, y1, y2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // y1=67, y2=-67</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：加、减、乘、除（整数之间做除法时，结果只保留整数部分而舍弃小数部分）、取模</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 5</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> + </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 5 + 2 = 7</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> - </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">-</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 5 - 2 = 3</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> × </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">*</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 5 × 2 = 10</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> / </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">/</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 5 / 2 = 2</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> %%</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> %d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">%</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 5 % 2 = 1</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><ul><li>示例：取模（运算结果的符号与被模数也就是第一个操作数相同。）</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> %</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;10 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%%</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, res1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 10 % 3 = 1</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> %</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;-10 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%%</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, res2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // -10 % 3 = -1</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res3 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> %</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;10 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%%</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> -3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, res3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 10 % -3 = 1</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res4 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">10</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> %</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;-10 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%%</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> -3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, res4);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // -10 % -3 = -1</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br></div></div><ul><li>示例：自增和自减</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 20</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i1</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">++</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i = 10</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i1 = 11</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> ++</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">i1;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i = 12</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i1 = 12</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i2</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">--</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i = 20</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i2 = 19</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> --</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">i2;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i = 18</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;i2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i2 = 18</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">/*</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 随意给出一个整数，打印显示它的个位数，十位数，百位数的值。</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 格式如下：</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 数字xxx的情况如下：</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 个位数：</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 十位数：</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 百位数：</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 例如：</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 数字153的情况如下：</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 个位数：3</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 十位数：5</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 百位数：1</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> */</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 153</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> bai </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">/</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> shi </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">%</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> /</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ge </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">%</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;百位为：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, bai);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;十位为：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, shi);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;个位为：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ge);</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br></div></div><h2 id="_2-3-关系运算符-比较运算符" tabindex="-1">2.3 关系运算符（比较运算符） <a class="header-anchor" href="#_2-3-关系运算符-比较运算符" aria-label="Permalink to &quot;2.3 关系运算符（比较运算符）&quot;">​</a></h2><ul><li>常见的关系运算符，如下所示：</li></ul><table tabindex="0"><thead><tr><th>运算符</th><th>描述</th><th>操作数个数</th><th>组成的表达式的值</th><th>副作用</th></tr></thead><tbody><tr><td><code>==</code></td><td>相等</td><td>2</td><td>0 或 1</td><td>❎</td></tr><tr><td><code>!=</code></td><td>不相等</td><td>2</td><td>0 或 1</td><td>❎</td></tr><tr><td><code>&lt;</code></td><td>小于</td><td>2</td><td>0 或 1</td><td>❎</td></tr><tr><td><code>&gt;</code></td><td>大于</td><td>2</td><td>0 或 1</td><td>❎</td></tr><tr><td><code>&lt;=</code></td><td>小于等于</td><td>2</td><td>0 或 1</td><td>❎</td></tr><tr><td><code>&gt;=</code></td><td>大于等于</td><td>2</td><td>0 或 1</td><td>❎</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① C 语言中，没有严格意义上的布尔类型，所以可以 0（假） 或 1（真）表示布尔类型的值。</li><li>② 不要将 <code>==</code> 写成 <code>=</code>，<code>==</code> 是比较运算符，而 <code>=</code> 是赋值运算符。</li><li>③ <code>&gt;=</code> 或 <code>&lt;=</code>含义是只需要满足 <code>大于或等于</code>、<code>小于或等于</code>其中一个条件，结果就返回真。</li></ul></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 8</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 7</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a &gt; b 的结果是：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a &gt; b 的结果是：1</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a &gt;= b 的结果是：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a &gt;= b 的结果是：1</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a &lt; b 的结果是：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a &lt; b 的结果是：0</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a &lt;= b 的结果是：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a &lt;= b 的结果是：0</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a == b 的结果是：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">==</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a == b 的结果是：0</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a != b 的结果是：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">!=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a != b 的结果是：1</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br></div></div><h2 id="_2-4-逻辑运算符" tabindex="-1">2.4 逻辑运算符 <a class="header-anchor" href="#_2-4-逻辑运算符" aria-label="Permalink to &quot;2.4 逻辑运算符&quot;">​</a></h2><ul><li>常见的逻辑运算符，如下所示：</li></ul><table tabindex="0"><thead><tr><th>运算符</th><th>描述</th><th>操作数个数</th><th>组成的表达式的值</th><th>副作用</th></tr></thead><tbody><tr><td><code>&amp;&amp;</code></td><td>逻辑与</td><td>2</td><td>0 或 1</td><td>❎</td></tr><tr><td>`</td><td></td><td>`</td><td>逻辑或</td><td>2</td></tr><tr><td><code>!</code></td><td>逻辑非</td><td>2</td><td>0 或 1</td><td>❎</td></tr></tbody></table><ul><li>逻辑运算符提供逻辑判断功能，用于构建更复杂的表达式，如下所示：</li></ul><table tabindex="0"><thead><tr><th>a</th><th>b</th><th>a &amp;&amp; b</th><th>a || b</th><th>!a</th></tr></thead><tbody><tr><td>1（真）</td><td>1（真）</td><td>1（真）</td><td>1（真）</td><td>0（假）</td></tr><tr><td>1（真）</td><td>0（假）</td><td>0（假）</td><td>1（真）</td><td>0（假）</td></tr><tr><td>0（假）</td><td>1（真）</td><td>0（假）</td><td>1（真）</td><td>1（真）</td></tr><tr><td>0（假）</td><td>0（假）</td><td>0（假）</td><td>0（假）</td><td>1（真）</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 对于逻辑运算符来说，任何非零值都表示真，零值表示假，如：<code>5 || 0</code> 返回 <code>1</code> ，<code>5 &amp;&amp; 0</code> 返回 <code>0</code> 。</li><li>② 短路现象： <ul><li>对于 <code>a &amp;&amp; b</code> 操作来说，当 a 为假(或 0 )时，因为 <code>a &amp;&amp; b</code> 结果必定为 0，所以不再执行表达式 b。</li><li>对于 <code>a || b</code> 操作来说，当 a 为真(或非 0 )时，因为 <code>a || b</code> 结果必定为 1，所以不再执行表达式 b。</li></ul></li></ul></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入整数a的值：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">a);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入整数b的值：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">b);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &gt; </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt; </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">// 短路现象</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> j </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> j</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">++</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> &gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;床前明月光</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 这行代码不会执行</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;我叫郭德纲</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, j);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> //10</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">// 短路现象</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> j </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">||</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> j</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">++</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> &gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;床前明月光 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;我叫郭德纲 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 这行代码不会被执行</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, j);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> //10</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h2 id="_2-5-赋值运算符" tabindex="-1">2.5 赋值运算符 <a class="header-anchor" href="#_2-5-赋值运算符" aria-label="Permalink to &quot;2.5 赋值运算符&quot;">​</a></h2><ul><li>常见的赋值运算符，如下所示：</li></ul><table tabindex="0"><thead><tr><th>运算符</th><th>描述</th><th>操作数个数</th><th>组成的表达式的值</th><th>副作用</th></tr></thead><tbody><tr><td><code>==</code></td><td>赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>+=</code></td><td>相加赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>-=</code></td><td>相减赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>*=</code></td><td>相乘赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>/=</code></td><td>相除赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>%=</code></td><td>取余赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>&lt;&lt;=</code></td><td>左移赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>&gt;&gt;=</code></td><td>右移赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>&amp;=</code></td><td>按位与赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td><code>^=</code></td><td>按位异或赋值</td><td>2</td><td>左边操作数的值</td><td>✅</td></tr><tr><td>`</td><td>=`</td><td>按位或赋值</td><td>2</td><td>左边操作数的值</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 赋值运算符的第一个操作数（左值）必须是变量的形式，第二个操作数可以是任何形式的表达式。</li><li>② 赋值运算符的副作用针对第一个操作数。</li></ul></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a = a + 3</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;a = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a = 6</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">-=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // b = b - 3</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;b = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // b = 0</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> c </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">*=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // c = c * 3</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;c = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, c);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // c = 9</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">/=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d = d / 3</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;d = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d = 1</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> e </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> e </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">%=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // e = e % 3</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;e = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, e);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // e = 0</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br></div></div><h2 id="_2-6-位运算符-了解" tabindex="-1">2.6 位运算符（了解） <a class="header-anchor" href="#_2-6-位运算符-了解" aria-label="Permalink to &quot;2.6 位运算符（了解）&quot;">​</a></h2><h3 id="_2-6-1-概述" tabindex="-1">2.6.1 概述 <a class="header-anchor" href="#_2-6-1-概述" aria-label="Permalink to &quot;2.6.1 概述&quot;">​</a></h3><ul><li>C 语言提供了一些位运算符，能够让我们操作二进制位（bit）。</li><li>常见的位运算符，如下所示。</li></ul><table tabindex="0"><thead><tr><th>运算符</th><th>描述</th><th>操作数个数</th><th>运算规则</th><th>副作用</th></tr></thead><tbody><tr><td><code>&amp;</code></td><td>按位与</td><td>2</td><td>两个二进制位都为 1 ，结果为 1 ，否则为 0 。</td><td>❎</td></tr><tr><td>`</td><td>`</td><td>按位或</td><td>2</td><td>两个二进制位只要有一个为 1（包含两个都为 1 的情况），结果为 1 ，否则为 0 。</td></tr><tr><td><code>^</code></td><td>按位异或</td><td>2</td><td>两个二进制位一个为 0 ，一个为 1 ，结果为 1，否则为 0 。</td><td>❎</td></tr><tr><td><code>~</code></td><td>按位取反</td><td>2</td><td>将每一个二进制位变成相反值，即 0 变成 1 ， 1 变 成 0 。</td><td>❎</td></tr><tr><td><code>&lt;&lt;</code></td><td>二进制左移</td><td>2</td><td>将一个数的各二进制位全部左移指定的位数，左 边的二进制位丢弃，右边补 0。</td><td>❎</td></tr><tr><td><code>&gt;&gt;</code></td><td>二进制右移</td><td>2</td><td>将一个数的各二进制位全部右移指定的位数，正数左补 0，负数左补 1，右边丢弃。</td><td>❎</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>操作数在进行位运算的时候，以它的补码形式计算！！！</p></div><h3 id="_2-6-2-输出二进制位" tabindex="-1">2.6.2 输出二进制位 <a class="header-anchor" href="#_2-6-2-输出二进制位" aria-label="Permalink to &quot;2.6.2 输出二进制位&quot;">​</a></h3><ul><li><p>在 C 语言中，<code>printf</code> 是没有提供输出二进制位的格式占位符的；但是，我们可以手动实现，以方便后期操作。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">/**</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> * 获取指定整数的二进制表示</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> * </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">@param</span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;"> num</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 整数</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> * </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">@return</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> 二进制表示的字符串，不包括前导的 &#39;0b&#39; 字符</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> */</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">char*</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> getBinary</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;"> num</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> static</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;"> binaryString</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">[</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">33</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">];</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i, j;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(num) </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">*</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 8</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, j </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">; i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">; i</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">--</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, j</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">++</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> const</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> bit </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;&gt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i) </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;"> binaryString</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">[j] </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> bit </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;0&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;"> binaryString</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">[j] </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\0</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> binaryString;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 17</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">12</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;整数 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 的二进制表示：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%s</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">getBinary</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(a));</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;整数 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 的二进制表示：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%s</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, b, </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">getBinary</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(b));</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br></div></div><h3 id="_2-6-3-按位与" tabindex="-1">2.6.3 按位与 <a class="header-anchor" href="#_2-6-3-按位与" aria-label="Permalink to &quot;2.6.3 按位与&quot;">​</a></h3><ul><li><p>按位与 <code>&amp;</code> 的运算规则是：如果二进制对应的位上都是 1 才是 1 ，否则为 0 ，即：</p><ul><li><code>1 &amp; 1</code> 的结果是 <code>1</code> 。</li><li><code>1 &amp; 0</code> 的结果是 <code>0</code> 。</li><li><code>0 &amp; 1</code> 的结果是 <code>0</code> 。</li><li><code>0 &amp; 0</code> 的结果是 <code>0</code> 。</li></ul></li><li><p>示例：<code>9 &amp; 7 = 1</code></p></li></ul><p><img src="/c/assets/17.DdAZIfeP.png" alt=""></p><ul><li>示例：<code>-9 &amp; 7 = 7</code></li></ul><p><img src="/c/assets/18.B4Zfj2jX.png" alt=""></p><h3 id="_2-6-4-按位或" tabindex="-1">2.6.4 按位或 <a class="header-anchor" href="#_2-6-4-按位或" aria-label="Permalink to &quot;2.6.4 按位或&quot;">​</a></h3><ul><li><p>按位与 <code>|</code> 的运算规则是：如果二进制对应的位上只要有 1 就是 1 ，否则为 0 ，即：</p><ul><li><code>1 | 1</code> 的结果是 <code>1</code> 。</li><li><code>1 | 0</code> 的结果是 <code>1</code> 。</li><li><code>0 | 1</code> 的结果是 <code>1</code> 。</li><li><code>0 | 0</code> 的结果是 <code>0</code> 。</li></ul></li><li><p>示例：<code>9 | 7 = 15</code></p></li></ul><p><img src="/c/assets/19.IfpA0D5n.png" alt=""></p><ul><li>示例：<code>-9 | 7 = -9</code></li></ul><p><img src="/c/assets/20.CfIzYazX.png" alt=""></p><h3 id="_2-6-5-按位异或" tabindex="-1">2.6.5 按位异或 <a class="header-anchor" href="#_2-6-5-按位异或" aria-label="Permalink to &quot;2.6.5 按位异或&quot;">​</a></h3><ul><li>按位与 <code>^</code> 的运算规则是：如果二进制对应的位上一个为 1 一个为 0 就为 1 ，否则为 0 ，即： <ul><li><code>1 ^ 1</code> 的结果是 <code>0</code> 。</li><li><code>1 ^ 0</code> 的结果是 <code>1</code> 。</li><li><code>0 ^ 1</code> 的结果是 <code>1</code> 。</li><li><code>0 ^ 0</code> 的结果是 <code>0</code> 。</li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>按位异或的场景有：</p><ul><li>① 交换两个数值：异或操作可以在不使用临时变量的情况下交换两个变量的值。</li><li>② 加密或解密：异或操作用于简单的加密和解密算法。</li><li>③ 错误检测和校正：异或操作可以用于奇偶校验位的计算和检测错误（RAID-3 以及以上）。</li><li>……</li></ul></div><ul><li>示例：<code>9 ^ 7 = 14</code></li></ul><p><img src="/c/assets/21.eHnZcbpI.png" alt=""></p><ul><li>示例：<code>-9 ^ 7 = -16</code></li></ul><p><img src="/c/assets/22.BNoKlM4o.png" alt=""></p><h3 id="_2-6-6-按位取反" tabindex="-1">2.6.6 按位取反 <a class="header-anchor" href="#_2-6-6-按位取反" aria-label="Permalink to &quot;2.6.6 按位取反&quot;">​</a></h3><ul><li><p>运算规则：如果二进制对应的位上是 1，则结果为0；如果是 0 ，则结果为 1 。</p><ul><li><code>~0</code> 的结果是 <code>1</code> 。</li><li><code>~1</code> 的结果是 <code>0</code> 。</li></ul></li><li><p>示例：<code>~9 = -10</code></p></li></ul><p><img src="/c/assets/23.CMVtwrqr.png" alt=""></p><ul><li>示例：<code>~-9 = 8</code></li></ul><p><img src="/c/assets/24.CN19KJG7.png" alt=""></p><h3 id="_2-6-7-二进制左移" tabindex="-1">2.6.7 二进制左移 <a class="header-anchor" href="#_2-6-7-二进制左移" aria-label="Permalink to &quot;2.6.7 二进制左移&quot;">​</a></h3><ul><li><p>在一定范围内，数据每向左移动一位，相当于原数据 * 2。（正数、负数都适用）</p></li><li><p>示例：<code>3 &lt;&lt; 4 = 48</code> （3 × 2^4）</p></li></ul><p><img src="/c/assets/25.BIhiJHjz.png" alt=""></p><ul><li>示例：<code>-3 &lt;&lt; 4 = -48</code> （-3 × 2 ^4）</li></ul><p><img src="/c/assets/26.A_E4n4g8.png" alt=""></p><h3 id="_2-6-7-二进制右移" tabindex="-1">2.6.7 二进制右移 <a class="header-anchor" href="#_2-6-7-二进制右移" aria-label="Permalink to &quot;2.6.7 二进制右移&quot;">​</a></h3><ul><li>在一定范围内，数据每向右移动一位，相当于原数据 / 2。（正数、负数都适用）</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 如果不能整除，则向下取整。</li><li>② 右移运算符最好只用于无符号整数，不要用于负数。因为不同系统对于右移后如何处理负数的符号位，有不同的做法，可能会得到不一样的结果。</li></ul></div><ul><li>示例：<code>69 &gt;&gt; 4 = 4</code> （69 / 2^4 ）</li></ul><p><img src="/c/assets/27.Bv4qFbwF.png" alt=""></p><ul><li>示例：<code>-69 &gt;&gt; 4 = -5</code> （-69 / 2^4 ）</li></ul><p><img src="/c/assets/28.IKaazo2J.png" alt=""></p><h2 id="_2-7-三元运算符" tabindex="-1">2.7 三元运算符 <a class="header-anchor" href="#_2-7-三元运算符" aria-label="Permalink to &quot;2.7 三元运算符&quot;">​</a></h2><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">条件表达式 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">?</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 表达式1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">:</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 表达式2 ;</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>如果条件表达式为非 0 （真），则整个表达式的值是表达式 1 。</li><li>如果条件表达式为 0 （假），则整个表达式的值是表达式 2 。</li></ul></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> m </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 110</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 20</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> result </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> m </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">?</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> m </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">:</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;result = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, result);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // result = 110</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><h2 id="_2-8-运算符优先级" tabindex="-1">2.8 运算符优先级 <a class="header-anchor" href="#_2-8-运算符优先级" aria-label="Permalink to &quot;2.8 运算符优先级&quot;">​</a></h2><ul><li>C 语言中运算符的优先级，如下所示：</li></ul><table tabindex="0"><thead><tr><th><strong>优先级</strong></th><th><strong>运算符</strong></th><th><strong>名称或含义</strong></th><th><strong>结合方向</strong></th></tr></thead><tbody><tr><td><strong>1</strong></td><td><code>[]</code></td><td>数组下标</td><td>左到右</td></tr><tr><td></td><td><code>()</code></td><td>圆括号</td><td></td></tr><tr><td></td><td><code>.</code></td><td>成员选择（对象）</td><td></td></tr><tr><td></td><td><code>-&gt;</code></td><td>成员选择（指针）</td><td></td></tr><tr><td><strong>2</strong></td><td><code>-</code></td><td>负号运算符</td><td>右到左</td></tr><tr><td></td><td><code>（类型）</code></td><td>强制类型转换</td><td></td></tr><tr><td></td><td><code>++</code></td><td>自增运算符</td><td></td></tr><tr><td></td><td><code>--</code></td><td>自减运算符</td><td></td></tr><tr><td></td><td><code>*</code></td><td>取值运算符</td><td></td></tr><tr><td></td><td><code>&amp;</code></td><td>取地址运算符</td><td></td></tr><tr><td></td><td><code>!</code></td><td>逻辑非运算符</td><td></td></tr><tr><td></td><td><code>~</code></td><td>按位取反运算符</td><td></td></tr><tr><td></td><td><code>sizeof</code></td><td>长度运算符</td><td></td></tr><tr><td><strong>3</strong></td><td><code>/</code></td><td>除</td><td>左到右</td></tr><tr><td></td><td><code>*</code></td><td>乘</td><td></td></tr><tr><td></td><td><code>%</code></td><td>余数（取模）</td><td></td></tr><tr><td><strong>4</strong></td><td><code>+</code></td><td>加</td><td>左到右</td></tr><tr><td></td><td><code>-</code></td><td>减</td><td></td></tr><tr><td><strong>5</strong></td><td><code>&lt;&lt;</code></td><td>左移</td><td>左到右</td></tr><tr><td></td><td><code>&gt;&gt;</code></td><td>右移</td><td></td></tr><tr><td><strong>6</strong></td><td><code>&gt;</code></td><td>大于</td><td>左到右</td></tr><tr><td></td><td><code>&gt;=</code></td><td>大于等于</td><td></td></tr><tr><td></td><td><code>&lt;</code></td><td>小于</td><td></td></tr><tr><td></td><td><code>&lt;=</code></td><td>小于等于</td><td></td></tr><tr><td><strong>7</strong></td><td><code>==</code></td><td>等于</td><td>左到右</td></tr><tr><td></td><td><code>!=</code></td><td>不等于</td><td></td></tr><tr><td><strong>8</strong></td><td><code>&amp;</code></td><td>按位与</td><td>左到右</td></tr><tr><td><strong>9</strong></td><td><code>^</code></td><td>按位异或</td><td>左到右</td></tr><tr><td><strong>10</strong></td><td>`</td><td>`</td><td>按位或</td></tr><tr><td><strong>11</strong></td><td><code>&amp;&amp;</code></td><td>逻辑与</td><td>左到右</td></tr><tr><td><strong>12</strong></td><td>`</td><td></td><td>`</td></tr><tr><td><strong>13</strong></td><td><code>?:</code></td><td>条件运算符</td><td>右到左</td></tr><tr><td><strong>14</strong></td><td><code>=</code></td><td>赋值运算符</td><td>右到左</td></tr><tr><td></td><td><code>/=</code></td><td>除后赋值</td><td></td></tr><tr><td></td><td><code>*=</code></td><td>乘后赋值</td><td></td></tr><tr><td></td><td><code>%=</code></td><td>取模后赋值</td><td></td></tr><tr><td></td><td><code>+=</code></td><td>加后赋值</td><td></td></tr><tr><td></td><td><code>-=</code></td><td>减后赋值</td><td></td></tr><tr><td></td><td><code>&lt;&lt;=</code></td><td>左移后赋值</td><td></td></tr><tr><td></td><td><code>&gt;&gt;=</code></td><td>右移后赋值</td><td></td></tr><tr><td></td><td><code>&amp;=</code></td><td>按位与后赋值</td><td></td></tr><tr><td></td><td><code>^=</code></td><td>按位异或后赋值</td><td></td></tr><tr><td></td><td>`</td><td>=`</td><td>按位或后赋值</td></tr><tr><td><strong>15</strong></td><td><code>,</code></td><td>逗号运算符</td><td>左到右</td></tr></tbody></table><div class="warning custom-block github-alert"><p class="custom-block-title">WARNING</p><p></p><ul><li>① 不要过多的依赖运算符的优先级来控制表达式的执行顺序，这样可读性太差，尽量<code>使用小括号来控制</code>表达式的执行顺序。</li><li>② 不要把一个表达式写得过于复杂，如果一个表达式过于复杂，则把它<code>分成几步</code>来完成。</li><li>③ 运算符优先级不用刻意地去记忆，总体上：一元运算符 &gt; 算术运算符 &gt; 关系运算符 &gt; 逻辑运算符 &gt; 三元运算符 &gt; 赋值运算符。</li></ul></div><h1 id="第三章-附录" tabindex="-1">第三章：附录 <a class="header-anchor" href="#第三章-附录" aria-label="Permalink to &quot;第三章：附录&quot;">​</a></h1><h2 id="_3-1-字符集和字符集编码" tabindex="-1">3.1 字符集和字符集编码 <a class="header-anchor" href="#_3-1-字符集和字符集编码" aria-label="Permalink to &quot;3.1 字符集和字符集编码&quot;">​</a></h2><h3 id="_3-3-1-概述" tabindex="-1">3.3.1 概述 <a class="header-anchor" href="#_3-3-1-概述" aria-label="Permalink to &quot;3.3.1 概述&quot;">​</a></h3><ul><li>字符集和字符集编码（简称编码）计算机系统中处理文本数据的两个基本概念，它们密切相关但又有区别。</li><li>字符集（Character Set）是一组字符的集合，其中每个字符都被分配了一个<code>唯一的编号</code>（通常是数字）。字符可以是字母、数字、符号、控制代码（如换行符）等。<code>字符集定义了可以表示的字符的范围</code>，但它并不直接定义如何将这些字符存储在计算机中。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>ASCII（美国信息交换标准代码）是最早期和最简单的字符集之一，它只包括了英文字母、数字和一些特殊字符，共 128 个字符。每个字符都分配给了一个从 0 到 127 的数字。</p></div><ul><li>字符集编码（Character Encoding，简称编码）是一种方案或方法，<code>它定义了如何将字符集中的字符转换为计算机存储和传输的数据（通常是一串二进制数字）</code>。简而言之，编码是字符到二进制数据之间的映射规则。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>ASCII编码方案定义了如何将 ASCII 字符集中的每个字符表示为 7 位的二进制数字。例如：大写字母<code>&quot;A&quot;</code>在ASCII 编码中表示为二进制的<code>1000001</code>，十进制的 <code>65</code> 。</p></div><ul><li><code>字符集</code>和<code>字符集编码</code>之间的关系如下：</li></ul><p><img src="/c/assets/29.CGTVELeO.png" alt=""></p><ul><li>Linux 中安装帮助手册：</li></ul><p><img src="/c/assets/30.Bz4_lEH0.gif" alt=""></p><h3 id="_3-3-2-ascii-编码" tabindex="-1">3.3.2 ASCII 编码 <a class="header-anchor" href="#_3-3-2-ascii-编码" aria-label="Permalink to &quot;3.3.2 ASCII 编码&quot;">​</a></h3><ul><li>从<code>冯·诺依曼</code>体系结构中，我们知道，计算机中所有的<code>数据</code>和<code>指令</code>都是以<code>二进制</code>的形式表示的；所以，计算机中对于文本数据的数据也是以二进制来存储的，那么对应的流程如下：</li></ul><p><img src="/c/assets/31.CcDWE4nn.png" alt=""></p><ul><li>我们知道，计算机是上个世纪 60 年代在美国研制成功的，为了实现字符和二进制的转换，美国就制定了一套字符编码，即英语字符和二进制位之间的关系，即 ASCII （American Standard Code for Information Interchange）编码： <ul><li>ASCII 编码只包括了英文字符、数字和一些特殊字符，一共 128 个字符，并且每个字符都分配了唯一的数字，范围是 0 - 127。</li><li>ASCII 编码中的每个字符都使用 7 位的二进制数字表示；但是，计算机中的存储的最小单位是 1 B = 8 位，那么最高位统一规定为 0 。</li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 其实，早期是没有字符集的概念的，只是后来为了解决乱码问题，而产生了字符集的概念。</li><li>② 对于英文体系来说，<code>a-zA-Z0-9</code>以及一些<code>特殊字符</code>一共 <code>128</code> 就可以满足实际存储需求；所以，在也是为什么 ASCII 码使用 7 位二进制（2^7 = 128 ）来存储的。</li></ul></div><ul><li>在操作系统中，就内置了对应的编码表，Linux 也不例外；可以使用如下的命令查看：</li></ul><div class="language-shell vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">shell</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">man</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> ascii</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><p><img src="/c/assets/32.B7y2_JVX.gif" alt=""></p><ul><li>其对应的 ASCII 编码表，如下所示：</li></ul><p><img src="/c/assets/33.Btcc3rs2.gif" alt=""></p><ul><li>但是，随着计算机的发展，计算机开始了东征之路，由美国传播到东方：</li></ul><p><img src="/c/assets/34.CR4ARW8y.png" alt=""></p><ul><li>先是传播到了欧洲，欧洲在兼容 ASCII 编码的基础上，推出了 ISO8859-1 编码，即： <ul><li>ISO8859-1 编码包括基本的拉丁字母表、数字、标点符号，以及西欧语言中特有的一些字符，如：法语中的 <code>è</code>、德语中的 <code>ü</code> 等。</li><li>ISO 8859-1 为每个字符分配一个单字节（8 位）编码，意味着它可以表示最多 256 （2^8）个不同的字符（编号从 0 到 255）。</li><li>ISO 8859-1 的前 128 个字符与 ASCII 编码完全一致，这使得 ASCII 编码的文本可以无缝转换为 ISO 8859-1 编码。</li></ul></li></ul><p><img src="/c/assets/33.Btcc3rs2.gif" alt=""></p><p><img src="/c/assets/36.DOX3ymYP.gif" alt=""></p><ul><li>计算机继续传播到了亚洲，亚洲（双字节）各个国家分别给出了自己国家对应的字符集编码，如： <ul><li>日本推出了 Shift-JIS 编码： <ul><li>单字节 ASCII 范围：0 - 127。</li><li>双字节范围： <ul><li>第一个字节：129 - 159 和 224 - 239 。</li><li>第二个字节：64 - 126 和 128 - 252 。</li></ul></li></ul></li><li>韩国推出了 EUC-KR 编码： <ul><li>单字节 ASCII 范围：0 - 127。</li><li>双字节范围：从 41281 - 65278。</li></ul></li><li>中国推出了 GBK 编码： <ul><li>单字节 ASCII 范围：0 - 127。</li><li>双字节范围：33088 - 65278 。</li></ul></li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 通过上面日本、韩国、中国的编码十进制范围，我们可以看到，虽然这些编码系统在技术上的编码范围存在重叠（特别是在高位字节区域），但因为它们各自支持的字符集完全不同，所以实际上它们并不直接冲突。</li><li>② 但是，如果一个中国人通过 GBK 编码写的文章，通过邮件发送给韩国人，因为韩国和中国在字符集编码上的高位字节有重叠部分，必然会造成歧义。</li></ul></div><h3 id="_3-3-3-unicode-编码" tabindex="-1">3.3.3 Unicode 编码 <a class="header-anchor" href="#_3-3-3-unicode-编码" aria-label="Permalink to &quot;3.3.3 Unicode 编码&quot;">​</a></h3><ul><li><p>在 Unicode 之前，世界上存在着数百种不同的编码系统，每一种编码系统都是为了支持特定语言或一组语言的字符集。这些编码系统，包括：ASCII、ISO 8859 系列、GBK、Shift-JIS、EUC-KR 等，它们各自有不同的字符范围和编码方式。这种多样性虽然在局部范围内解决了字符表示的问题，但也带来了以下几个方面的挑战：</p><ul><li><code>编码冲突</code>：由于不同的编码系统可以为相同的字节值分配不同的字符，因此在不同编码之间转换文本时，如果没有正确处理编码信息，就很容易产生乱码。这种编码冲突在尝试处理多种语言的文本时尤为突出。</li><li><code>编码的复杂性</code>：随着全球化的发展，软件和系统需要支持越来越多的语言，这就要求开发者和系统同时处理多种不同的编码系统。这不仅增加了开发和维护的复杂性，而且也增加了出错的风险。</li><li><code>资源限制</code>：在早期计算机技术中，内存和存储资源相对有限。不同的编码标准要求系统存储多套字符集数据，这无疑增加了对有限资源的消耗。</li><li>……</li></ul></li><li><p>针对上述的种种问题，为了推行全球化，Unicode 应运而生，Unicode 的核心规则和设计原则是建立一个全球统一的字符集，使得世界上所有的文字和符号都能被唯一地识别和使用，无论使用者位于何地或使用何种语言。这套规则包括了字符的编码、表示、处理和转换机制，旨在确保不同系统和软件间能够无缝交换和处理文本数据。</p><ul><li><code>通用字符集 (UCS)</code>：Unicode 为每一个字符分配一个唯一的编号（称为<code>“码点”</code>）。这些码点被组织在一个统一的字符集中，官方称之为 “通用字符集”（Universal Character Set，UCS）。码点通常表示为 <code>U+</code> 后跟一个十六进制数，例如：<code>U+0041</code> 代表大写的英文字母 <code>“A”</code>。</li><li><code>编码平面和区段</code>：Unicode 码点被划分为多个 “平面（Planes）”，每个平面包含 65536（16^4）个码点。目前，Unicode定义了 17 个平面（从 0 到16），每个平面被分配了一个编号，从 “基本多文种平面（BMP）” 的 0 开始，到 16 号平面结束。这意味着 Unicode 理论上可以支持超过 110万（17*65536）个码点。</li></ul></li><li><p>Unicode 仅仅只是字符集，给每个字符设置了唯一的数字编号而已，却没有给出这些数字编号实际如何存储，可以通过如下命令查看：</p></li></ul><p><img src="/c/assets/37.Cie9_tkP.gif" alt=""></p><ul><li>为了在计算机系统中表示 Unicode 字符，定义了几种编码方案，这些方案包括 UTF-8、UTF-16 和 UTF-32 等。 <ul><li><strong>UTF-8</strong>：使用 1 - 4 个字节表示每个 Unicode 字符，兼容 ASCII，是网络上最常用的编码。</li><li><strong>UTF-16</strong>：使用 2 - 4 个字节表示每个 Unicode 字符，适合于需要经常处理基本多文种平面之外字符的应用。</li><li><strong>UTF-32</strong>：使用固定的 4 个字节表示每个 Unicode 字符，简化了字符处理，但增加了存储空间的需求。</li></ul></li><li><code>Unicode 字符集</code>和对应的<code>UTF-8 字符编码</code>之间的关系，如下所示：</li></ul><p><img src="/c/assets/38.DLjH9Ges.png" alt=""></p></div></div></main><footer class="VPDocFooter" data-v-39a288b8 data-v-d4a0bba5><!--[--><!--]--><div class="edit-info" data-v-d4a0bba5><!----><div class="last-updated" data-v-d4a0bba5><p class="VPLastUpdated" data-v-d4a0bba5 data-v-7e05ebdb>上次更新: <time 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