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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="'+t+'" alt="" loading="lazy"></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="'+h+`" alt="" loading="lazy"></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="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><ul><li><p>① 数据类型在内存中占用的存储单元（字节数），就称为该数据类型的长度（步长），如：short 占用 2 个字节的内存，就称 short 的长度（步长）是 2。</p></li><li><p>② C 语言并没有严格规定各种整数数据类型在内存中所占存储单元的长度，只做了宽泛的限制：</p><ul><li>short 至少占用 2 个字节的存储单元。</li><li>int 建议为一个机器字长（指计算机的处理器在一次操作中能够处理的二进制数据的位数，机器字长是处理器的“字”长度，它决定了处理器在一个时钟周期内能够处理的数据量，如：早期的计算机的处理器通常是 8 位的机器字长，意味着处理器一次只能处理 8 位（二进制）数据；之后的计算机的处理器有 16 位的机器字长，意味着处理器一次可以处理 16 位的数据；再之后计算机的处理器有 32 位或 64 位的机器字长，意味着处理器一次可以处理 32 位或 64位的数据）。即：32 位环境下 int 占用 4 个字节的存储单元，64 位环境下 int 占用 8 个字节的存储单元。</li><li>short 的长度（步长）不能大于 int，long 的长度（步长）不能小于 int，long long 不能小于 long。</li></ul></li><li><p>③ 那么，各种整数数据类型在内存中所占存储单元的长度的公式就是 <code>2 ≤ sizeof(short) ≤ sizeof(int) ≤ sizeof(long) ≤ sizeof(long long)</code>，具体的存储空间由编译系统自行决定。其中，<code>sizeof</code> 是测量类型或变量、常量长度的<code>运算符</code>。</p></li></ul></div><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><ul><li>① 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>② 整型分为有符号 signed 和无符号 unsigned 两种，默认是 signed。</li><li>③ 在实际开发中，<code>最常用的整数类型</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>④ 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，早已经解决了必须通过<code>格式占位符</code>来才能将变量进行输入和输出。</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>
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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 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>
<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 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>
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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="_1-2-6-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><p>① sizeof 是运算符，不是内置函数。</p></li><li><p>② 表达式可以是任何类型的数据类型、变量或常量。</p></li><li><p>③ 用来获取某种数据类型、变量或常量占用的字节数量（内存中的存储单元），并且 <code>sizeof(...)</code> 的<code>返回值类型</code>是 <code>size_t</code> ；并且，如果是变量名称，可以省略 <code>()</code>；如果是数据类型，则不能省略 <code>()</code>。</p></li><li><p>④ 在 <code>printf</code> 中使用占位符 <code>%zu</code> 来处理 <code>size_t</code> 类型的值。</p></li><li><p>⑤ 之前，也提过，C 语言没有一个统一的官方机构来制定或强制执行其标准，而是由一个标准委员会负责制定标准。不同的编译器可以选择部分或完全遵循这些标准。因此，C 语言的编译器实现可能会有所不同，这就要求程序员在编写跨平台代码时特别注意数据类型的大小和布局。</p></li><li><p>⑥ 与 C 语言不同，Java 和 JavaScript 等语言的标准是强制性的。在 Java 语言中，<code>int</code> 类型在所有平台上都是 4 个字节，无论是在 Linux、MacOS 还是 Windows 上。因此，这些语言不需要像 C 语言那样依赖 <code>sizeof</code> 来处理不同平台上的数据类型大小差异，因为编译器已经在底层处理了这些差异。换言之，<code>sizeof</code> 运算符在 C 语言中的重要性在于它为程序员提供了一个处理不同平台上数据类型大小差异的工具。当然，如果你在 C 语言中，使用精确宽度类型，如：<code>int8_t</code>、<code>int16_t</code>、<code>int32_t</code>、<code>uint8_t</code>、 <code>uint16_t</code>、<code>uint32_t</code> 等，也可以确保代码在各个平台上的一致性。</p></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><h2 id="_1-3-数值溢出" tabindex="-1">1.3 数值溢出 <a class="header-anchor" href="#_1-3-数值溢出" aria-label="Permalink to &quot;1.3 数值溢出&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，如果一个容器的容量是固定的，我们不停的向其中注入水，那么当容器中充满水之后，继续注入，就会溢出，如下所示：</li></ul><p><img src="`+e+'" alt="" loading="lazy"></p><ul><li>在程序中也是一样的，各种整数类型在内存中占用的存储单元是不同的，如：short 在内存中占用 2 个字节的存储单元，int 在内存中占用 4 个字节的存储单元。这也就意味着，各种整数类型只能存储有限的数值，当数值过大或多小的时候，超出的部分就会被直接截掉，那么数值就不能正确的存储，我们就将这种现象就称为<code>溢出</code>（overflow）。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>如果这个数目前是<code>最大值</code>，再进行<code>加法</code>计算，数据就会超过该类型能够表示的最大值，叫做<code>上溢出</code>（如果最大值 + 1 会“绕回”到最小值）。</li><li>如果这个数目前是<code>最小值</code>，再进行<code>减法</code>计算，数据就会超过该类型能够表示的最小值， 叫做<code>下溢出</code>（如果最小值 - 1 会“绕回”到最大值）。</li></ul><p>在 C 语言中，程序产生数值溢出的时候，并不会引起错误而自动停止，是因为计算机直接按照二进制补码的运算规则进行处理；但是，这可能会导致不可预料的后果。因此，编程时要特别注意避免数值溢出，特别是在涉及大数或小数的运算时。</p></div><h3 id="_1-3-2-无符号数的取值范围" tabindex="-1">1.3.2 无符号数的取值范围 <a class="header-anchor" href="#_1-3-2-无符号数的取值范围" aria-label="Permalink to &quot;1.3.2 无符号数的取值范围&quot;">​</a></h3><ul><li>在 C 语言中，<code>无符号数</code>（unsigned 类型）的取值范围（最大值和最小值）的计算是很容易的，即：将内存中的所有位，设置为 <code>0</code> 就是<code>最小值</code>，设置为 <code>1</code> 就是<code>最大值</code>。</li></ul><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><p>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。</p></div><ul><li>以 <code>unsigned char</code> 类型为例，它在内存中占用的存储单元是 1 个字节，即 8 位。如果所有位都设置为 <code>0</code> ，它的最小值就是 <code>0</code> ；如果所有位设置为 <code>1</code> ，它的最大值就是 <code>2⁸ - 1 = 255</code> ，如下所示：</li></ul><p><img src="'+k+`" alt="" loading="lazy"></p><ul><li>那么，<code>unsigned char</code> 的最大值是如何计算出来的？最简单的方法就是这样的，如下所示：</li></ul><div class="language-txt vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">txt</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span>  1 × 2⁰ + 1 × 2¹ + 1 × 2² + 1 × 2³ + 1 × 2⁴ + 1 × 2⁵ + 1 × 2⁶ + 1 × 2⁷ </span></span>
<span class="line"><span>= 1 + 2 + 4 + 8 + 16 + 32 + 64 + 128 </span></span>
<span class="line"><span>= 255</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></div></div><ul><li>但是，这种计算方法虽然有效，但是非常麻烦，如果是 8 个字节的 long ，那么计算就非常麻烦了（可能要计算半天）。当然，我们也知道，这就是等比数列（高中知识），等比数列的公式，如下所示：</li></ul>`,104),W={class:"MathJax",jax:"SVG",style:{direction:"ltr",position:"relative"}},Y={style:{overflow:"visible","min-height":"1px","min-width":"1px","vertical-align":"-0.912ex"},xmlns:"http://www.w3.org/2000/svg",width:"15.075ex",height:"2.893ex",role:"img",focusable:"false",viewBox:"0 -875.7 6663.1 1278.6","aria-hidden":"true"},$=a('<g stroke="currentColor" fill="currentColor" stroke-width="0" transform="scale(1,-1)"><g data-mml-node="math"><g data-mml-node="msub"><g data-mml-node="mi"><path data-c="1D446" d="M308 24Q367 24 416 76T466 197Q466 260 414 284Q308 311 278 321T236 341Q176 383 176 462Q176 523 208 573T273 648Q302 673 343 688T407 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github-dark vp-code" tabindex="0"><code><span class="line"><span>  1111 1111 + 1 - 1</span></span>
<span class="line"><span>= 10000 0000 - 1</span></span>
<span class="line"><span>= 2⁹⁻¹ - 1</span></span>
<span class="line"><span>= 2⁸ - 1 </span></span>
<span class="line"><span>= 255</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></div></div><ul><li>其对应的换算过程，如下所示：</li></ul><p><img src="`+d+'" alt="" loading="lazy"></p><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><ul><li>① 当内存中所有的位都是 1 的时候，这种“凑整”的技巧非常实用！！！</li><li>② 按照上述的技巧，我们可以很容易得计算出： <ul><li><code>unsinged char</code>（1 个字节） 的取值范围是：<code>[0, 2⁸ - 1]</code>。</li><li><code>unsinged short</code>（2 个字节）的取值范围是：<code>[0, 2¹⁶ - 1]</code>。</li><li><code>unsinged int</code>（4 个字节）的取值范围是：<code>[0, 2³² - 1]</code>。</li><li><code>unsinged long</code>（8 个字节）的取值范围是：<code>[0, 2⁶⁴ - 1]</code>。</li></ul></li></ul></div><h3 id="_1-3-3-有符号数的取值范围" tabindex="-1">1.3.3 有符号数的取值范围 <a class="header-anchor" href="#_1-3-3-有符号数的取值范围" aria-label="Permalink to &quot;1.3.3 有符号数的取值范围&quot;">​</a></h3><ul><li>在 C 语言中，<code>有符号数</code>（signed 类型）在计算机底层是以<code>补码</code>的形式存储的（计算的时候，也是以补码的形式进行计算的，并且符号位参与计算）；但是，在读取的时候，需要采用<code>逆向</code>的转换，即：将补码转换为原码。</li></ul><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><p>在 C 语言中，有符号整数，最高位是符号位，用于表示正负数。</p></div><ul><li>以 <code>char</code> 类型为例，它的取值范围，如下所示：</li></ul><table tabindex="0"><thead><tr><th>补码</th><th>反码</th><th>原码</th><th>值</th></tr></thead><tbody><tr><td>1111 1111</td><td>1111 1110</td><td>1000 0001</td><td>-1</td></tr><tr><td>1111 1110</td><td>1111 1101</td><td>1000 0010</td><td>-2</td></tr><tr><td>1111 1101</td><td>1111 1100</td><td>1000 0011</td><td>-3</td></tr><tr><td>...</td><td>...</td><td>...</td><td>...</td></tr><tr><td>1000 0011</td><td>1000 0010</td><td>1111 1101</td><td>-125</td></tr><tr><td>1000 0010</td><td>1000 0001</td><td>1111 1110</td><td>-126</td></tr><tr><td>1000 0001</td><td>1000 0000</td><td>1111 1111</td><td>-127</td></tr><tr><td><strong>1000 0000</strong></td><td><strong>---</strong></td><td><strong>---</strong></td><td><strong>-128</strong></td></tr><tr><td>0111 1111</td><td>0111 1111</td><td>0111 1111</td><td>127</td></tr><tr><td>0111 1110</td><td>0111 1110</td><td>0111 1110</td><td>126</td></tr><tr><td>0111 1101</td><td>0111 1101</td><td>0111 1101</td><td>125</td></tr><tr><td>...</td><td>...</td><td>...</td><td>...</td></tr><tr><td>0000 0010</td><td>0000 0010</td><td>0000 0010</td><td>2</td></tr><tr><td>0000 0001</td><td>0000 0001</td><td>0000 0001</td><td>1</td></tr><tr><td>0000 0000</td><td>0000 0000</td><td>0000 0000</td><td>0</td></tr></tbody></table><ul><li>从上面的列表中，我们可以得知，<code>char</code> 类型的取值范围是：<code>[-2⁸, 2⁸ - 1]</code>，即：<code>[-128, 127]</code>。</li><li>对于 <code>-128</code> 而言，它的补码是 <code>1000 0000</code>，是无法按照传统的补码表示法来计算原码的，因为在补码转换到反码的时候需要 <code>-1</code> ，而 <code>1000 0000 - 1</code>需要向高位借 <code>1</code> ，而最高位是符号位是不能借的，这就非常矛盾。</li></ul><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><p>计算机规定，<code>1000 0000</code> 这个特殊的补码就表示 <code>-128</code> 。</p></div><ul><li>但是，为什么偏偏是 <code>-128</code> ，而不是其它数字？是因为 <code>-128</code> 使得 <code>char</code> 类型的取值范围保持连贯，中间没有“空隙”。如果我们按照传统的方式来计算 <code>-128</code> 的补码，如下所示： <ul><li>① 原码：在原码表示法中，-128 的数据位是 <code>1000 0000</code>，但是 char 的数据位只有 <code>7</code> 位，那么最高位 <code>1</code> 就变为了符号位，剩下的数据位就是 <code>000 0000</code>；所以，<code>-128</code> 的原码就是 <code>1000 0000</code>。</li><li>② 反码：对数据位取反，-128 的反码就是：<code>1111 1111</code> 。</li><li>③ 补码：在反码的基础上 <code>+1</code>，得到 <code>1000 0000</code>，是因为符号位被覆盖了，补码最终依然是 <code>1000 0000</code>。</li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p><code>-128</code> 从原码转换到补码的过程中，符号位被 <code>1</code> 覆盖了两次，而负数的符号位本来就是 <code>1</code>，被 <code>1</code> 覆盖多少次也不会影响到数字的符号。</p></div><ul><li>虽然从 <code>1000 0000</code> 这个补码推算不出 <code>-128</code>，但是从 <code>-128</code> 却能推算出 <code>1000 0000</code> 这个补码，即：有符号数在存储之前先要转换为补码。</li></ul><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><ul><li>① 通过这种方式，<code>-128</code> 就成为了补码的最小值 <code>1000 0000</code>，而这个值不会与其他任何正数或负数的补码冲突。 <ul><li>如果采用<code>原码</code>存储，那么将会出现 <code>+0</code> 和 <code>-0</code> 的情况，即：<code>0000 0000</code>、<code>1000 0000</code>，这样在取值范围内，就存在两个相同的值，多此一举。</li><li>如果采用<code>原码</code>存储，最大值不变是 <code>127</code> ，但是最小值只能存储到 <code>-127</code> ，不能存储到 <code>-128</code>，因为 <code>-128</code> 的原码是 <code>1000 0000</code>，和 <code>-0</code> 的原码冲突。</li></ul></li><li>② 这就是补码系统的强大之处，它能让整数的范围连贯，并且实现了加法和减法的统一处理。</li><li>③ 按照上述的方法，我们可以很容易得计算出： <ul><li><code>char</code>（1 个字节） 的取值范围是：<code>[-2⁸, 2⁸ - 1]</code>。</li><li><code>short</code>（2 个字节）的取值范围是：<code>[-2¹⁶, 2¹⁶ - 1]</code>。</li><li><code>int</code>（4 个字节）的取值范围是：<code>[-2³², 2³² - 1]</code>。</li><li><code>long</code>（8 个字节）的取值范围是：<code>[-2⁶⁴, 2⁶⁴ - 1]</code>。</li></ul></li></ul></div><h3 id="_1-3-4-数值溢出" tabindex="-1">1.3.4 数值溢出 <a class="header-anchor" href="#_1-3-4-数值溢出" aria-label="Permalink to &quot;1.3.4 数值溢出&quot;">​</a></h3><ul><li>对于<code>无符号</code>的数值溢出： <ul><li>当数据到达最大值的时候，再 <code>+1</code> 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 <code>-1</code> 就会回到无符号数的最大值。</li></ul></li></ul><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><ul><li>① 对于无符号整数的运算，如：加、减、乘、除、取余等，其最小值是 0 ，最大值是 <code>2^n - 1</code> 。如果某个计算结果超出了这个范围，计算机会自动将结果对 <code>2^N</code> 取余（模），从而丢失高位，只保留低位。</li><li>② 以 <code>8</code> 位无符号整数而言，最大值是 <code>255</code>（1111 1111）；那么， <code>255 + 1</code> 的结果就是 <code>(2^8 -1 + 1) % 2^8 = 0</code>，商是 <code>256</code>。</li><li>③ 以 <code>8</code> 位无符号整数而言，最小值是 <code>0</code>（0000 0000），那么， <code>0 - 1</code> 的结果就是 <code>(0 - 1) % 2^8 = 255</code>，商是 <code>-1</code>。</li></ul></div><ul><li>那么，<code>无符号</code>的<code>上溢出</code>，原理就是这样的：</li></ul><p><img src="'+r+'" alt="" loading="lazy"></p><ul><li>那么，<code>无符号</code>的<code>下溢出</code>，原理就是这样的：</li></ul><p><img src="'+c+'" alt="" loading="lazy"></p><ul><li><p>对于<code>有符号</code>的数值溢出：</p><ul><li>当数据到达最大值的时候，再 <code>+1</code> 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 <code>-1</code> 就会回到有符号数的最大值。</li></ul></li><li><p>那么，<code>有符号</code>的<code>上溢出</code>，原理就是这样的：</p></li></ul><p><img src="'+E+'" alt="" loading="lazy"></p><ul><li>那么，<code>有符号</code>的<code>下溢出</code>，原理就是这样的：</li></ul><p><img src="'+g+`" alt="" loading="lazy"></p><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><ul><li>① 在实际开发中，选择合适的数据类型，以避免数值溢出问题！！！</li><li>② 数据溢出错误会导致软件运算结果出错，如：1996 年的亚利安5号运载火箭爆炸、2004 年的 Comair 航空公司航班停飞事故。</li></ul></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="_1-4-浮点类型" tabindex="-1">1.4 浮点类型 <a class="header-anchor" href="#_1-4-浮点类型" aria-label="Permalink to &quot;1.4 浮点类型&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="`+F+'" alt="" loading="lazy"></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="'+o+`" alt="" loading="lazy"></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，而科学计数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="_1-4-2-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>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="_1-4-3-字面量后缀" tabindex="-1">1.4.3 字面量后缀 <a class="header-anchor" href="#_1-4-3-字面量后缀" aria-label="Permalink to &quot;1.4.3 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="_1-4-4-类型占用的内存大小-存储空间" tabindex="-1">1.4.4 类型占用的内存大小（存储空间） <a class="header-anchor" href="#_1-4-4-类型占用的内存大小-存储空间" aria-label="Permalink to &quot;1.4.4 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="_1-4-5-类型的取值范围" tabindex="-1">1.4.5 类型的取值范围 <a class="header-anchor" href="#_1-4-5-类型的取值范围" aria-label="Permalink to &quot;1.4.5 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="_1-5-字符类型" tabindex="-1">1.5 字符类型 <a class="header-anchor" href="#_1-5-字符类型" aria-label="Permalink to &quot;1.5 字符类型&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>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>① 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>② 像拉丁体系（英文）文字，如：a-z、A-Z、0-9 以及一些特殊符号，只需要单个字节的内存存储空间就能存储的，我们就称为窄类型；而像中文、日文等单个字节的内存空间存储不了的，我们就称为宽类型。</li><li>③ 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>④ 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>⑤ 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="_1-5-2-格式占位符" tabindex="-1">1.5.2 格式占位符 <a class="header-anchor" href="#_1-5-2-格式占位符" aria-label="Permalink to &quot;1.5.2 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="_1-5-3-类型占用的内存大小-存储空间" tabindex="-1">1.5.3 类型占用的内存大小（存储空间） <a class="header-anchor" href="#_1-5-3-类型占用的内存大小-存储空间" aria-label="Permalink to &quot;1.5.3 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="_1-5-4-类型的取值范围" tabindex="-1">1.5.4 类型的取值范围 <a class="header-anchor" href="#_1-5-4-类型的取值范围" aria-label="Permalink to &quot;1.5.4 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="_1-5-5-字符类型的本质" tabindex="-1">1.5.5 字符类型的本质 <a class="header-anchor" href="#_1-5-5-字符类型的本质" aria-label="Permalink to &quot;1.5.5 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="`+y+'" alt="" loading="lazy"></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="'+u+`" alt="" loading="lazy"></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="_1-6-布尔类型" tabindex="-1">1.6 布尔类型 <a class="header-anchor" href="#_1-6-布尔类型" aria-label="Permalink to &quot;1.6 布尔类型&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>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="_1-6-2-早期的布尔类型" tabindex="-1">1.6.2 早期的布尔类型 <a class="header-anchor" href="#_1-6-2-早期的布尔类型" aria-label="Permalink to &quot;1.6.2 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:#6A737D;--shiki-dark:#6A737D;">	// 禁用 stdout 缓冲区</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">    setbuf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(stdout, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">NULL</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><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><h3 id="_1-6-3-宏定义的布尔类型" tabindex="-1">1.6.3 宏定义的布尔类型 <a class="header-anchor" href="#_1-6-3-宏定义的布尔类型" aria-label="Permalink to &quot;1.6.3 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 style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">    // 禁用 stdout 缓冲区</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">    setbuf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(stdout, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">NULL</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:#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><span class="line-number">22</span><br><span class="line-number">23</span><br></div></div><h3 id="_1-6-4-c99-标准中的布尔类型" tabindex="-1">1.6.4 C99 标准中的布尔类型 <a class="header-anchor" href="#_1-6-4-c99-标准中的布尔类型" aria-label="Permalink to &quot;1.6.4 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 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;">    // 禁用 stdout 缓冲区</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">    setbuf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(stdout, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">NULL</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;">   temp;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 使用 int 类型的变量临时存储输入</span></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;">temp);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">    // 将输入值转换为 _Bool 类型</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">    handsome </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (temp </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:#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><span class="line-number">22</span><br></div></div><h3 id="_1-6-5-c99-标准头文件中的布尔类型-推荐" tabindex="-1">1.6.5 C99 标准头文件中的布尔类型（推荐） <a class="header-anchor" href="#_1-6-5-c99-标准头文件中的布尔类型-推荐" aria-label="Permalink to &quot;1.6.5 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;stdbool.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 style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;string.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;">    // 禁用 stdout 缓冲区</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">    setbuf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(stdout, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">NULL</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:#E36209;--shiki-dark:#FFAB70;"> input</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 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>
<span class="line"><span style="--shiki-light:#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;">%s</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, input);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 使用 %s 读取字符串</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">    // 将输入字符串转换为布尔值</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">    if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">strcmp</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(input, </span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;true&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) </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:#24292E;--shiki-dark:#E1E4E8;">        handsome </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> true</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:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">strcmp</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(input, </span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;false&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) </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:#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:#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;无效输入！</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:#D73A49;--shiki-dark:#F97583;">        return</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:#24292E;--shiki-dark:#E1E4E8;">    }</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><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><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br></div></div><h2 id="_1-7-数据类型转换" tabindex="-1">1.7 数据类型转换 <a class="header-anchor" href="#_1-7-数据类型转换" aria-label="Permalink to &quot;1.7 数据类型转换&quot;">​</a></h2><h3 id="_1-7-1-概述" tabindex="-1">1.7.1 概述 <a class="header-anchor" href="#_1-7-1-概述" aria-label="Permalink to &quot;1.7.1 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="_1-7-2-自动类型转换-隐式转换" tabindex="-1">1.7.2 自动类型转换（隐式转换） <a class="header-anchor" href="#_1-7-2-自动类型转换-隐式转换" aria-label="Permalink to &quot;1.7.2 自动类型转换（隐式转换）&quot;">​</a></h3><h4 id="_1-7-2-1-运算过程中的自动类型转换" tabindex="-1">1.7.2.1 运算过程中的自动类型转换 <a class="header-anchor" href="#_1-7-2-1-运算过程中的自动类型转换" aria-label="Permalink to &quot;1.7.2.1 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="`+b+'" alt="" loading="lazy"></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="'+m+`" alt="" loading="lazy"></p><div class="warning custom-block github-alert"><p class="custom-block-title">WARNING</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="_1-7-2-2-赋值时的自动类型转换" tabindex="-1">1.7.2.2 赋值时的自动类型转换 <a class="header-anchor" href="#_1-7-2-2-赋值时的自动类型转换" aria-label="Permalink to &quot;1.7.2.2 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+`" alt="" loading="lazy"></p><div class="warning custom-block github-alert"><p class="custom-block-title">WARNING</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="caution custom-block github-alert"><p class="custom-block-title">CAUTION</p><p></p><p>强制类型转换可能会导致精度损失！！！</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><h2 id="_1-8-再谈数据类型" tabindex="-1">1.8 再谈数据类型 <a class="header-anchor" href="#_1-8-再谈数据类型" aria-label="Permalink to &quot;1.8 再谈数据类型&quot;">​</a></h2><ul><li><p>通过之前的知识，我们知道，CPU 是直接和内存打交道的，CPU 在处理数据的时候，会将数据临时存放到内存中。内存那么大，CPU 是怎么找到对应的数据的？</p></li><li><p>首先，CPU 会将内存按照字节（1 Bytes = 8 bit，我们也称为存储单元）进行划分，如下所示：</p></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>这些存储单元中，存储的都是 0 和 1 这样的数据，因为计算机只能识别二进制数。</p></div><p><img src="`+B+'" alt="" loading="lazy"></p><ul><li>并且，为了方便管理，每个独立的小单元格，即：存储单元，都有自己唯一的编号（内存地址），如下所示：</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>之所以，要给每个存储单元加上内存地址，就是为了<code>加快</code>数据的<code>存取速度</code>，可以类比生活中的<code>字典</code>以及<code>快递单号</code>。</p></div><p><img src="'+A+'" alt="" loading="lazy"></p><ul><li>我们在定义变量的时候，是这么定义的，如下所示：</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;"> 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></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>上述的代码其实透露了三个重要的信息：</p><ul><li>① 数据存储在哪里。</li><li>② 数据的长度是多少。</li><li>③ 数据的处理方式。</li></ul></div><ul><li>其实，在编译器对程序进行编译的时候，是这样做的，如下所示：</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 编译器在编译的时候，就将变量替换为内存中存储单元的内存地址（知道了你家的门牌号），这样就可以方便的进行存取数据了（解答了上述的问题 ① ）。</li><li>② 变量中其实存储的是初始化值 10 在内存中存储单元的首地址，我们也知道，数据类型 int 的存储空间是 4 个字节，那么根据首地址 + 4 个字节就可以完整的将数据从内存空间中取出来或存进去（解答了上述的问题 ② ）。</li><li>③ 我们知道，数据在计算机底层的存储方式是不一样的，如：整数在计算机底层的存储就是计算机补码的方式，浮点数在计算机底层的存储类似于科学计数法；但是，字符类型在计算机底层的存储和整数以及浮点数完全不同，需要查码表，即：在存储的时候，需要先查询码表，转换为二进制进行存储；在读取的时候，也需要先查询码表，将二进制转换为对应的字符（解答了上述的问题 ③ ）。</li></ul></div><div class="important custom-block github-alert"><p class="custom-block-title">IMPORTANT</p><p></p><ul><li>① 数据类型只在定义变量的时候声明，而且必须声明；在使用变量的时候，就无需再声明，因为此时的数据类型已经确定的。</li><li>② 在实际开发中，我们通常将普通变量等价于内存中某个区域的值（底层到底是怎么转换的，那是编译器帮我们完成的，我们通常无需关心，也没必要关心）。</li><li>③ 某些动态的编程语言，如：JavaScript ，在定义变量的时候，是不需要给出数据类型的，编译器会根据赋值情况自动推断出变量的数据类型，貌似很智能；但是，这无疑增加了编译器的工作，降低了程序的性能（动态一时爽，重构火葬场，说的就是动态编程语言，不适合大型项目的开发；所以，之后微软推出了 TypeScript ，就是为了给 JavaScript 增加强类型系统，以提高开发和运行效率）。</li></ul></div><p><img src="'+D+'" alt="" loading="lazy"></p><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="'+v+'" alt="" loading="lazy"></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="'+T+`" alt="" loading="lazy"></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><li>⑤ 对于 <code>i++</code> 或 <code>i--</code> ，各种编程语言的用法和支持是不同的，例如：C/C++、Java 等完全支持，Python 压根一点都不支持，Go 语言虽然支持 <code>i++</code> 或 <code>i--</code> ，却只支持这些操作符作为独立的语句，并且不能嵌入在其它的表达式中。</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>
<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;"> 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>
<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;"> 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>
<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;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>
<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：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>
<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;"> 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>
<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;">%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>
<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：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>
<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;"> 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>
<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;"> 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>
<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：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>
<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></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，可以使用 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><code>||</code></td><td>逻辑或</td><td>2</td><td>0 或 1</td><td>❎</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<code>非零值</code>都表示<code>真</code>，<code>零值</code>表示<code>假</code>，如：<code>5 || 0</code> 返回 <code>1</code> ，<code>5 &amp;&amp; 0</code> 返回 <code>0</code> 。</li><li>② 逻辑运算符的理解： <ul><li><code>&amp;&amp;</code> 的理解就是：<code>两边条件，同时满足</code>。</li><li><code>||</code>的理解就是：<code>两边条件，二选一</code>。</li><li><code>!</code> 的理解就是：<code>条件取反</code>。</li></ul></li><li>③ 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><code>|=</code></td><td>按位或赋值</td><td>2</td><td>左边操作数的值</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 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>
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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>
<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>
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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>
<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>
<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></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><code>|</code></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><td>❎</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="`+Q+'" alt="" loading="lazy"></p><ul><li>示例：<code>-9 &amp; 7 = 7</code></li></ul><p><img src="'+q+'" alt="" loading="lazy"></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="'+f+'" alt="" loading="lazy"></p><ul><li>示例：<code>-9 | 7 = -9</code></li></ul><p><img src="'+_+'" alt="" loading="lazy"></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="'+x+'" alt="" loading="lazy"></p><ul><li>示例：<code>-9 ^ 7 = -16</code></li></ul><p><img src="'+w+'" alt="" loading="lazy"></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="'+L+'" alt="" loading="lazy"></p><ul><li>示例：<code>~-9 = 8</code></li></ul><p><img src="'+z+'" alt="" loading="lazy"></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="'+H+'" alt="" loading="lazy"></p><ul><li>示例：<code>-3 &lt;&lt; 4 = -48</code> （-3 × 2 ^4）</li></ul><p><img src="'+P+'" alt="" loading="lazy"></p><h3 id="_2-6-8-二进制右移" tabindex="-1">2.6.8 二进制右移 <a class="header-anchor" href="#_2-6-8-二进制右移" aria-label="Permalink to &quot;2.6.8 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="'+M+'" alt="" loading="lazy"></p><ul><li>示例：<code>-69 &gt;&gt; 4 = -5</code> （-69 ÷ 2^4 ）</li></ul><p><img src="'+I+`" alt="" loading="lazy"></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>➡️（从左到右）</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>⬅️（从右到左）</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>➡️（从左到右）</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>➡️（从左到右）</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>➡️（从左到右）</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>➡️（从左到右）</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>➡️（从左到右）</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>➡️（从左到右）</td></tr><tr><td><strong>9</strong></td><td><code>^</code></td><td>按位异或</td><td>➡️（从左到右）</td></tr><tr><td><strong>10</strong></td><td><code>|</code></td><td>按位或</td><td>➡️（从左到右）</td></tr><tr><td><strong>11</strong></td><td><code>&amp;&amp;</code></td><td>逻辑与</td><td>➡️（从左到右）</td></tr><tr><td><strong>12</strong></td><td><code>||</code></td><td>逻辑或</td><td>➡️（从左到右）</td></tr><tr><td><strong>13</strong></td><td><code>?:</code></td><td>条件运算符</td><td>⬅️（从右到左）</td></tr><tr><td><strong>14</strong></td><td><code>=</code></td><td>赋值运算符</td><td>⬅️（从右到左）</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><code>|=</code></td><td>按位或后赋值</td><td></td></tr><tr><td><strong>15</strong></td><td><code>,</code></td><td>逗号运算符</td><td>➡️（从左到右）</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>&#39;A&#39;</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="`+V+'" alt="" loading="lazy"></p><ul><li>Linux 中安装帮助手册：</li></ul><p><img src="'+N+'" alt="" loading="lazy"></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="'+S+'" alt="" loading="lazy"></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="'+O+'" alt="" loading="lazy"></p><ul><li>其对应的 ASCII 编码表，如下所示：</li></ul><p><img src="'+U+'" alt="" loading="lazy"></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="'+Z+'" alt="" loading="lazy"></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="'+R+'" alt="" loading="lazy"></p><p><img src="'+j+'" alt="" loading="lazy"></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="'+G+'" alt="" loading="lazy"></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="'+J+'" alt="" loading="lazy"></p>',273);function ks(ds,rs,cs,Es,gs,Fs){return l(),n("div",null,[K,s("p",null,[s("mjx-container",W,[(l(),n("svg",Y,ss)),is])]),s("ul",null,[s("li",null,[s("p",null,[i("那么，结果就是："),s("mjx-container",as,[(l(),n("svg",ns,ps)),ts])])]),hs]),es])}const us=p(X,[["render",ks]]);export{ys as __pageData,us as 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