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data-v-3f215769></div><!--[--><!--]--><!----><!--[--><!--]--><!--[--><!--]--></div></div></div></div><div class="content" data-v-39a288b8><div class="content-container" data-v-39a288b8><!--[--><!--]--><main class="main" data-v-39a288b8><div style="position:relative;" class="vp-doc _c_notes_01_c-basic_03_xdx_" data-v-39a288b8><div><h1 id="第一章-数据类型-⭐" tabindex="-1">第一章:数据类型(⭐) <a class="header-anchor" href="#第一章-数据类型-⭐" aria-label="Permalink to "第一章:数据类型(⭐)""></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 "1.1 概述""></a></h2><ul><li><p>根据<code>变量</code>中<code>存储</code>的<code>值</code>的<code>不同</code>,我们可以将<code>变量</code>分为两类:</p><ul><li><code>普通变量</code>:变量所对应的内存中存储的是<code>普通值</code>。</li><li><code>指针变量</code>:变量所对应的内存中存储的是<code>另一个变量的地址</code>。</li></ul></li><li><p>如下图所示:</p></li></ul><p><img src="/c/assets/1.L8V3GBrc.png" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>普通变量和指针变量的相同点:</p><ul><li>普通变量有内存空间,指针变量也有内存空间。</li><li>普通变量有内存地址,指针变量也有内存地址。</li><li>普通变量所对应的内存空间中有值,指针变量所对应的内存空间中也有值。</li></ul><p>普通变量和指针变量的不同点:</p><ul><li>普通变量所对应的内存空间存储的是普通的值,如:整数、小数、字符等;指针变量所对应的内存空间存储的是另外一个变量的地址。</li><li>普通变量有普通变量的运算方式,而指针变量有指针变量的运算方式(后续讲解)。</li></ul></div><ul><li>那么,在 C 语言中变量的数据类型就可以这么划分,如下所示:</li></ul><p><img src="/c/assets/2.BkF1yWLn.png" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>根据<code>普通变量</code>中<code>存储</code>的<code>值</code>的类型不同,可以将<code>普通变量类型</code>划分为<code>基本数据类型</code>(整型、字符类型、浮点类型、布尔类型)和<code>复合数据类型</code>(数组类型、结构体类型、共用体类型、枚举类型)。</li><li>根据<code>指针变量</code>所<code>指向空间</code>中<code>存储</code>的<code>值</code>的类型不同,可以将<code>指针类型</code>分为<code>基本数据类型指针</code>、<code>复合数据类型指针</code>、<code>函数指针</code>、<code>数组指针</code>等,例如:如果指针所指向的空间保存的是 int 类型,那么该指针就是 int 类型的指针。</li></ul></div><h2 id="_1-2-整数类型" tabindex="-1">1.2 整数类型 <a class="header-anchor" href="#_1-2-整数类型" aria-label="Permalink to "1.2 整数类型""></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 "1.2.1 概述""></a></h3><ul><li>整数类型简称整型,用于存储整数值,如:12、20、50 等。</li><li>根据所占<code>内存空间</code>大小的不同,可以将整数类型划分为:</li><li>① 短整型:</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间(内存空间)</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned short (无符号短整型)</td><td>2 字节</td><td>0 ~ 65,535 (2^16 - 1)</td></tr><tr><td>[signed] short(有符号短整型,默认)</td><td>2 字节</td><td>-32,768 (- 2^15) ~ 32,767 (2^15 -1)</td></tr></tbody></table><ul><li>② 整型:</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间(内存空间)</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned int(无符号整型)</td><td>4 字节(通常)</td><td>0 ~ 4294967295 (0 ~2^32 -1)</td></tr><tr><td>[signed] int(有符号整型,默认)</td><td>4 字节(通常)</td><td>-2147483648(- 2^31) ~ 2147483647 (2^31-1)</td></tr></tbody></table><ul><li>③ 长整型:</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间(内存空间)</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned long(无符号长整型)</td><td>4 字节(通常)</td><td>0 ~2^32 -1</td></tr><tr><td>[signed] long(有符号长整型,默认)</td><td>4 字节(通常)</td><td>- 2^31 ~ 2^31-1</td></tr></tbody></table><ul><li>④ 长长整型:</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储空间(内存空间)</th><th>取值范围</th></tr></thead><tbody><tr><td>unsigned long long(无符号长整型)</td><td>8 字节(通常)</td><td>0 ~2^64 -1</td></tr><tr><td>[signed] long long(有符号长整型,默认)</td><td>8 字节(通常)</td><td>- 2^63 ~ 2^63-1</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① C 语言默认没有规定各种数据类型所占存储单元的长度,但是通常需要遵守:<code>sizeof(short int) ≤ sizeof(int) ≤ sizeof(long int) ≤ sizeof(long long)</code> ,具体的存储空间由编译系统自行决定;其中,sizeof 是测量类型或变量、常量长度的运算符。</li><li>② short 至少 2 个字节,long 至少 4 个字节。</li><li>③ 之所以这么规定,是为了可以让 C 语言长久使用,因为目前主流的 CPU 都是 64 位,但是在 C语言刚刚出现的时候,CPU 还是以 8 位和 16 位为主。如果当时就将整型定死为 8 位或 16 位,那么现在我们肯定不会再学习 C 语言了。</li><li>④ 整型分为有符号 signed 和无符号 unsigned 两种,默认是 signed。</li><li>⑤ 在实际开发中,<code>最常用的整数类型</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>⑥ C 语言中的<code>格式占位符</code>非常多,只需要大致了解即可;因为,我们在实际开发中,一般都会使用 C++ 或 Rust 以及其它的高级编程语言,如:Java 等,早已经解决了需要通过<code>格式占位符</code>来输入和输出变量。</li></ul></div><h3 id="_1-2-2-短整型-了解" tabindex="-1">1.2.2 短整型(了解) <a class="header-anchor" href="#_1-2-2-短整型-了解" aria-label="Permalink to "1.2.2 短整型(了解)""></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 <limits.h></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;"> <stdio.h></span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义有符号 short 类型</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // s1 = -100</span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义无符号 short 类型</span></span>
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<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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // s2 = 100</span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义 short 类型,默认是有符号</span></span>
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<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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // s3 = -200</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><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;"> <stdio.h></span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> 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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 2</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> s2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> short</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 2</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><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;"> <limits.h></span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stdio.h></span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, USHRT_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [0,65535]</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, SHRT_MIN,SHRT_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [-32768,32767]</span></span>
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<span class="line"></span>
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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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></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 "1.2.3 整型""></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 <limits.h></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;"> <stdio.h></span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义有符号 int 类型</span></span>
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<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>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i1 = -100</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义无符号 int 类型</span></span>
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<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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i2 = 100</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义 int 类型,默认是有符号</span></span>
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<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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // i3 = -200</span></span>
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||
<span class="line"></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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><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;"> <stdio.h></span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
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<span class="line"></span>
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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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><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;"> <limits.h></span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stdio.h></span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, UINT_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [0,4294967295]</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, INT_MIN,INT_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [-2147483648,2147483647]</span></span>
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<span class="line"></span>
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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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></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 "1.2.4 长整型(了解)""></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 <limits.h></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;"> <stdio.h></span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义有符号 long 类型</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> l1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // l1 = -100</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义无符号 long 类型</span></span>
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<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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // l2 = 100</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义 long 类型,默认是有符号</span></span>
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<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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // l3 = -200</span></span>
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<span class="line"></span>
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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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><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;"> <stdio.h></span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, l3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
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<span class="line"></span>
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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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><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;"> <limits.h></span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stdio.h></span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ULONG_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [0,4294967295]</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</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>
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<span class="line"></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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></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 "1.2.5 长长整型(了解)""></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 <limits.h></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;"> <stdio.h></span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义有符号 long long 类型</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> signed</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> long</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ll1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // ll1 = -100</span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义无符号 long long 类型</span></span>
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<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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // ll2 = 100</span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义 long long 类型,默认是有符号</span></span>
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<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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // ll3 = -200</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><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;"> <stdio.h></span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> 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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 8</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> 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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 8</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ll3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 8</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><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;"> <limits.h></span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stdio.h></span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, ULLONG_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [0,18446744073709551615]</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</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>
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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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></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 "1.2.6 字面量后缀""></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;"> <stdio.h></span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"></span>
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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;"> 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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"num = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num = 100</span></span>
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<span class="line"></span>
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<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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"num2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%ld\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num2 = 100</span></span>
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<span class="line"></span>
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<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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"num3 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lld\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num3 = 100</span></span>
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<span class="line"></span>
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<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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"num4 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%u\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num4);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num4 = 100</span></span>
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<span class="line"></span>
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<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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"num5 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lu\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num5);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num5 = 100</span></span>
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<span class="line"></span>
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<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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"num6 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%llu\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num6);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // num6 = 100</span></span>
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||
<span class="line"></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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><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 "1.2.7 精确宽度类型""></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><stdint.h></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;"> <stdio.h></span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stdint.h></span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"></span>
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<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>
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<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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, x32);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // x32 = 45933945</span></span>
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<span class="line"></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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></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 "1.2.8 sizeof 运算符""></a></h3><ul><li>语法:</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(表达式)</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 表达式可以是任何类型的数据类型、变量或常量。</li><li>② 返回某种数据类型或某个值占用的字节数量,并且 <code>sizeof(...)</code> 的<code>返回值类型</code>是 <code>size_t</code> 。</li><li>③ 在 <code>printf</code> 中使用占位符 <code>%zu</code> 来处理 <code>size_t</code> 类型的值。</li></ul></div><ul><li>示例:参数是数据类型</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stdio.h></span></span>
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||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stddef.h></span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> size_t</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 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>
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<span class="line"></span>
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||
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"</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;"> <stdio.h></span></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stddef.h></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;">"</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;">"</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;"> <stdio.h></span></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stddef.h></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;">"</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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, s);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 4</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><h3 id="_1-2-9-数值溢出" tabindex="-1">1.2.9 数值溢出 <a class="header-anchor" href="#_1-2-9-数值溢出" aria-label="Permalink to "1.2.9 数值溢出""></a></h3><ul><li><p>所谓的数值溢出指的是:当超过一个数据类型能够存放的最大范围的时候,数值就会溢出。</p><ul><li>如果达到了最大值,再进行加法计算,数据就会超过该类型能够表示的最大值,叫做上溢出。</li><li>如果这个数目前是最小值,再进行减法计算, 数据就会超过该类型的最小值, 叫做下溢出。</li></ul></li><li><p>在 C 语言中,<code>整数</code>的<code>数据类型</code>分为<code>无符号</code>和<code>有符号</code>的,其在底层表示和存储是不一样的,即:</p><ul><li><code>无符号整数不使用最高位作为符号位</code>,所有的位都用于表示数值,如:对于一个 4 位无符号整数,二进制表示的范围是从 0000 到 1111 ,那么十进制表示的范围是从 0 到 15。</li><li><code>有符号整数使用最高位作为符号位</code>,这意味着它们可以表示正数和负数,通常使用补码来表示有符号整数。在补码表示法中:最高位为 0 表示正数、最高位为 1 表示负数,如:对于一个4位有符号整数,二进制表示的范围是从 0000(0) 到 0111 (7),1000 (-8)到 1111(-1)。</li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>在 C 语言中,无符号整数,最高位不是符号位,它是数值的一部分。</li><li>在 C 语言中,有符号整数,最高位是符号位,用于表示正负数。</li></ul></div><ul><li><p>对于无符号的数值溢出:</p><ul><li>当数据到达最大值的时候,再加 1 就会回到无符号数的最小值。</li><li>当数据达到最小值的时候,再减 1 就会回到无符号数的最大值。</li></ul></li><li><p>那么,无符号的上溢出,原理就是这样的:</p></li></ul><p><img src="/c/assets/3.CceY8r_n.png" alt=""></p><ul><li>那么,无符号的下溢出,原理就是这样的(需要先借位,然后再减):</li></ul><p><img src="/c/assets/4.DHaUgOwj.png" alt=""></p><ul><li><p>对于有符号的数值溢出:</p><ul><li>当数据到达最大值的时候,再加 1 就会回到有符号数的最小值。</li><li>当数据达到最小值的时候,再减 1 就会回到有符号数的最大值。</li></ul></li><li><p>那么,有符号的上溢出,原理就是这样的:</p></li></ul><p><img src="/c/assets/5.CXGaq_zh.png" alt=""></p><ul><li>那么,有符号的下溢出,原理就是这样的:</li></ul><p><img src="/c/assets/6.BrZYAEEl.png" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>在实际开发中,选择合适的数据类型,以避免数值溢出问题!!!</p></div><ul><li>示例:无符号的上溢出和下溢出</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <limits.h></span></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stdio.h></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;">"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;">"</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;">"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;">"</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;"> <limits.h></span></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stdio.h></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;">"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;">"</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;">"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;">"</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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><h2 id="_1-3-浮点类型" tabindex="-1">1.3 浮点类型 <a class="header-anchor" href="#_1-3-浮点类型" aria-label="Permalink to "1.3 浮点类型""></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 "1.3.1 概述""></a></h3><ul><li>在生活中,我们除了使用<code>整数</code>,如:18、25 之外,还会使用到<code>小数</code>,如:3.1415926、6.18 等,<code>小数</code>在计算机中也被称为<code>浮点数</code>(和底层存储有关)。</li><li><code>整数</code>在计算机底层的存储被称为<code>定点存储</code>,如下所示:</li></ul><p><img src="/c/assets/7.DpCroFHv.png" alt=""></p><ul><li><code>小数</code>在计算机底层的存储被称为<code>浮点存储</code>,如下所示:</li></ul><p><img src="/c/assets/8.Cr7P0Gji.png" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 计算机底层就是采取类似科学计数法的形式来存储小数的,而科学技术法的表现就是这样的,如:3.12 * 10^-2 ;其中,10 是基数,-2 是指数,而 3.12 是尾数。</li><li>② 因为尾数区的内存空间的宽度不同,导致了小数的精度也不相同,所以小数在计算机中也称为浮点数。</li></ul></div><ul><li>在 C 语言中,变量的浮点类型,如下所示:</li></ul><table tabindex="0"><thead><tr><th>类型</th><th>存储大小</th><th>值的范围</th><th>有效小数位数</th></tr></thead><tbody><tr><td>float(单精度)</td><td>4 字节</td><td>1.2E-38 ~ 3.4E+38</td><td>6 ~ 9</td></tr><tr><td>double(双精度)</td><td>8 字节</td><td>2.3E-308 ~ 1.7E+308</td><td>15 ~ 18</td></tr><tr><td>long double(长双精度)</td><td>16 字节</td><td>3.4E-4932 ~ 1.2E+4932</td><td>18 或更多</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 各类型的存储大小和精度受到操作系统、编译器、硬件平台的影响。</li><li>② 浮点型数据有两种表现形式: <ul><li>十进制数形式:3.12、512.0f、0.512(.512,可以省略 0 )</li><li>科学计数法形式:5.12e2(e 表示基数 10)、5.12E-2(E 表示基数 10)。</li></ul></li><li>③ 在实际开发中,对于浮点类型,建议使用 double 类型;如果范围不够,就使用 long double 类型。</li></ul></div><h3 id="_1-3-2-格式占位符" tabindex="-1">1.3.2 格式占位符 <a class="header-anchor" href="#_1-3-2-格式占位符" aria-label="Permalink to "1.3.2 格式占位符""></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;"> <stdio.h></span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> 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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, f1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // f1 = 10.000000</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, f1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // f1 = 10.00</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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></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;"> <stdio.h></span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"></span>
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<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>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1 = 13.141593</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1 = 13.14</span></span>
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<span class="line"></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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></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;"> <stdio.h></span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"></span>
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<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>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1 = 13.141593</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d1 = 13.14</span></span>
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<span class="line"></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>
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||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></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;"> <stdio.h></span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"></span>
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<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>
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<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>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, f1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // f1 = 3.14</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d2 = 314.00</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</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>
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||
<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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br></div></div><h3 id="_1-3-3-字面量后缀" tabindex="-1">1.3.3 字面量后缀 <a class="header-anchor" href="#_1-3-3-字面量后缀" aria-label="Permalink to "1.3.3 字面量后缀""></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;"> <stdio.h></span></span>
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||
<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;">"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;">"</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;">"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;">"</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;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, d3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d3 = 3.1416</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br></div></div><h3 id="_1-3-4-类型占用的内存大小-存储空间" tabindex="-1">1.3.4 类型占用的内存大小(存储空间) <a class="header-anchor" href="#_1-3-4-类型占用的内存大小-存储空间" aria-label="Permalink to "1.3.4 类型占用的内存大小(存储空间)""></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;"> <stdio.h></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;">"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;">"</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;">"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;">"</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;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">long</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">));</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 16</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><h3 id="_1-3-5-类型的取值范围" tabindex="-1">1.3.5 类型的取值范围 <a class="header-anchor" href="#_1-3-5-类型的取值范围" aria-label="Permalink to "1.3.5 类型的取值范围""></a></h3><ul><li><p>可以通过 <code>#include <float.h></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;"> <float.h></span></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stdio.h></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;">"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;">"</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;">"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;">"</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;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, LDBL_MIN, LDBL_MAX);</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><h2 id="_1-4-字符类型" tabindex="-1">1.4 字符类型 <a class="header-anchor" href="#_1-4-字符类型" aria-label="Permalink to "1.4 字符类型""></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 "1.4.1 概述""></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>'1'</code>、<code>'A'</code>、<code>'&'</code>。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>C 语言的出现在 1972 年,由美国人丹尼斯·里奇设计出来;那个时候,只需要 1 个字节的内存空间,就可以完美的表示拉丁体系(英文)文字,如:a-z、A-Z、0-9 以及一些特殊符号;所以,C 语言中不支持多个字节的字符,如:中文、日文等。</li><li>C 语言中没有字符串类型,是使用字符数组(char 数组)来模拟字符串的,并且字符数组也不是字符串,而是构造类型。</li><li>在 C 语言中,如果想要输出中文、日文等多字节字符,就需要使用字符数组(char 数组)。</li><li>在 C++、Java 等高级编程语言中,已经提供了 String (字符串)类型,原生支持 Unicode,可以方便地处理多语言和特殊字符。</li></ul></div><ul><li>在 C 语言中,可以使用<code>转义字符 \</code>来表示特殊含义的字符。</li></ul><table tabindex="0"><thead><tr><th><strong>转义字符</strong></th><th><strong>说明</strong></th></tr></thead><tbody><tr><td><code>\b</code></td><td>退格</td></tr><tr><td><code>\n</code></td><td>换行符</td></tr><tr><td><code>\r</code></td><td>回车符</td></tr><tr><td><code>\t</code></td><td>制表符</td></tr><tr><td><code>\"</code></td><td>双引号</td></tr><tr><td><code>\'</code></td><td>单引号</td></tr><tr><td><code>\\</code></td><td>反斜杠</td></tr><tr><td>...</td><td></td></tr></tbody></table><h3 id="_1-4-2-格式占位符" tabindex="-1">1.4.2 格式占位符 <a class="header-anchor" href="#_1-4-2-格式占位符" aria-label="Permalink to "1.4.2 格式占位符""></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;"> <stdio.h></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;"> '&'</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;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, c);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // c = &</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;"> 'a'</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;">"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;">"</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;"> 'A'</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;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, c3);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // c3 = A</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br></div></div><h3 id="_1-4-3-类型占用的内存大小-存储空间" tabindex="-1">1.4.3 类型占用的内存大小(存储空间) <a class="header-anchor" href="#_1-4-3-类型占用的内存大小-存储空间" aria-label="Permalink to "1.4.3 类型占用的内存大小(存储空间)""></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;"> <stdio.h></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;">"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;">"</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;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">sizeof</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">unsigned</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">));</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 1</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br></div></div><h3 id="_1-4-4-类型的取值范围" tabindex="-1">1.4.4 类型的取值范围 <a class="header-anchor" href="#_1-4-4-类型的取值范围" aria-label="Permalink to "1.4.4 类型的取值范围""></a></h3><ul><li><p>可以通过 <code>#include <limits.h></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;"> <limits.h></span></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stdio.h></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;">"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;">"</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;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, UCHAR_MAX);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // [0,255]</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><h3 id="_1-4-3-字符类型的本质" tabindex="-1">1.4.3 字符类型的本质 <a class="header-anchor" href="#_1-4-3-字符类型的本质" aria-label="Permalink to "1.4.3 字符类型的本质""></a></h3><ul><li>在 C 语言中,char 本质上就是一个整数,是 ASCII 码中对应的数字,占用的内存大小是 1 个字节(存储空间),所以 char 类型也可以进行数学运算。</li></ul><p><img src="/c/assets/9.NlBmD7pA.png" alt=""></p><ul><li>char 类型同样分为 signed char(无符号)和 unsigned char(有符号),其中 signed char 取值范围-128 ~ 127,unsigned char取值范围 0 ~ 255,默认是否带符号取决于当前运行环境。</li><li><code>字符类型的数据</code>在计算机中<code>存储</code>和<code>读取</code>的过程,如下所示:</li></ul><p><img src="/c/assets/10.ZiBq6Pno.png" alt=""></p><ul><li>示例:</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <limits.h></span></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stdio.h></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;"> 'A'</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;"> '9'</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;"> '</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\t</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'</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;">"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;">"</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;"> 'b'</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;">"</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;">"</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;">"</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;">"</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;">"</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;">"</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;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, c1, c2, c3);</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br></div></div><h2 id="_1-5-布尔类型" tabindex="-1">1.5 布尔类型 <a class="header-anchor" href="#_1-5-布尔类型" aria-label="Permalink to "1.5 布尔类型""></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 "1.5.1 概述""></a></h3><ul><li>布尔值用于表示 true(真)、false(假)两种状态,通常用于逻辑运算和条件判断。</li></ul><h3 id="_1-5-2-早期的布尔类型" tabindex="-1">1.5.2 早期的布尔类型 <a class="header-anchor" href="#_1-5-2-早期的布尔类型" aria-label="Permalink to "1.5.2 早期的布尔类型""></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;"> <stdio.h></span></span>
|
||
<span class="line"></span>
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||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
|
||
<span class="line"><span 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;">"帅不帅[0 丑,1 帅]: "</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;">"</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&</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;">"你真的很帅!!!"</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;">"你真的很丑!!!"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h3 id="_1-5-3-宏定义的布尔类型" tabindex="-1">1.5.3 宏定义的布尔类型 <a class="header-anchor" href="#_1-5-3-宏定义的布尔类型" aria-label="Permalink to "1.5.3 宏定义的布尔类型""></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;"> <stdio.h></span></span>
|
||
<span class="line"></span>
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||
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">// 宏定义</span></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#define</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> BOOL</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#define</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> TRUE</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#define</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> FALSE</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> BOOL handsome </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"帅不帅[FALSE 丑,TRUE 帅]: "</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;">"</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&</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;">"你真的很帅!!!"</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;">"你真的很丑!!!"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br></div></div><h3 id="_1-5-4-c99-标准中的布尔类型" tabindex="-1">1.5.4 C99 标准中的布尔类型 <a class="header-anchor" href="#_1-5-4-c99-标准中的布尔类型" aria-label="Permalink to "1.5.4 C99 标准中的布尔类型""></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;"> <stdio.h></span></span>
|
||
<span class="line"></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> _Bool</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> handsome </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"帅不帅[0 丑,1 帅]: "</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;">"</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&</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;">"你真的很帅!!!"</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;">"你真的很丑!!!"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h3 id="_1-5-5-c99-标准头文件中的布尔类型-推荐" tabindex="-1">1.5.5 C99 标准头文件中的布尔类型(推荐) <a class="header-anchor" href="#_1-5-5-c99-标准头文件中的布尔类型-推荐" aria-label="Permalink to "1.5.5 C99 标准头文件中的布尔类型(推荐)""></a></h3><ul><li>在 C99 中提供了一个头文件 <code><stdbool.h></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;"> <stdio.h></span></span>
|
||
<span class="line"></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> bool</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> handsome </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> false</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"帅不帅[false 丑,true 帅]: "</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;">"</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&</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;">"你真的很帅!!!"</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;">"你真的很丑!!!"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h2 id="_1-6-数据类型转换" tabindex="-1">1.6 数据类型转换 <a class="header-anchor" href="#_1-6-数据类型转换" aria-label="Permalink to "1.6 数据类型转换""></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 "1.6.1 概述""></a></h3><ul><li>在 C 语言编程中,经常需要对不同类型的数据进行运算,运算前需要先转换为同一类型,再运算。为了解决数据类型不一致的问题,需要对数据的类型进行转换。</li></ul><h3 id="_1-6-2-自动类型转换-隐式转换" tabindex="-1">1.6.2 自动类型转换(隐式转换) <a class="header-anchor" href="#_1-6-2-自动类型转换-隐式转换" aria-label="Permalink to "1.6.2 自动类型转换(隐式转换)""></a></h3><h4 id="_1-6-2-1-运算过程中的自动类型转换" tabindex="-1">1.6.2.1 运算过程中的自动类型转换 <a class="header-anchor" href="#_1-6-2-1-运算过程中的自动类型转换" aria-label="Permalink to "1.6.2.1 运算过程中的自动类型转换""></a></h4><ul><li>不同类型的数据进行混合运算的时候,会发生数据类型转换,<code>窄类型会自动转换为宽类型</code>,这样就不会造成精度损失。</li></ul><p><img src="/c/assets/11.DAgmsf-w.png" alt=""></p><ul><li>转换规则: <ul><li>① 不同类型的整数进行运算的时候,窄类型整数会自动转换为宽类型整数。</li><li>② 不同类型的浮点数进行运算的时候,精度小的类型会自动转换为精度大的类型。</li><li>③ 整数和浮点数进行运算的时候,整数会自动转换为浮点数。</li></ul></li><li>转换方向:</li></ul><p><img src="/c/assets/12.B2iC37fw.png" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>最好避免无符号整数与有符号整数的混合运算,因为这时 C 语言会自动将 signed int 转为 unsigned int ,可能不会得到预期的结果。</p></div><ul><li>示例:</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stdio.h></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;">"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;">"</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;"> <stdio.h></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;">"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;">"</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;"> <stdio.h></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;">"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;">"</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;"> <stdio.h></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;">"</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2lf</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, result);</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h4 id="_1-6-2-2-赋值时的自动类型转换" tabindex="-1">1.6.2.2 赋值时的自动类型转换 <a class="header-anchor" href="#_1-6-2-2-赋值时的自动类型转换" aria-label="Permalink to "1.6.2.2 赋值时的自动类型转换""></a></h4><ul><li>在赋值运算中,赋值号两边量的数据类型不同时,等号右边的类型将转换为左边的类型。</li><li>如果窄类型赋值给宽类型,不会造成精度损失;如果宽类型赋值给窄类型,会造成精度损失。</li></ul><p><img src="/c/assets/14.BlE3ZFud.png" alt=""></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>C 语言在检查类型匹配方面不太严格,最好不要养成这样的习惯。</p></div><ul><li>示例:</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stdio.h></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;">"a2: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2f\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"b2: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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 "1.6.3 强制类型转换""></a></h3><ul><li>隐式类型转换中的宽类型赋值给窄类型,编译器是会产生警告的,提示程序存在潜在的隐患,如果非常明确地希望转换数据类型,就需要用到强制(或显式)类型转换。</li><li>语法:</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">数据类型 变量名 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (类型名)变量、常量或表达式;</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>强制类型转换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;"> <stdio.h></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 -> 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;">"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;">"</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;">"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;">"</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;">"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;">"</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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><h1 id="第二章-运算符-⭐" tabindex="-1">第二章:运算符(⭐) <a class="header-anchor" href="#第二章-运算符-⭐" aria-label="Permalink to "第二章:运算符(⭐)""></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 "2.1 概述""></a></h2><ul><li>运算符是一种特殊的符号,用于数据的运算、赋值和比较等。</li><li><code>表达式</code>指的是一组运算数、运算符的组合,表达式<code>一定具有值</code>,一个变量或一个常量可以是表达式,变量、常量和运算符也可以组成表达式,如:</li></ul><p><img src="/c/assets/15.CdvhiwcU.png" alt=""></p><ul><li><code>操作数</code>指的是<code>参与运算</code>的<code>值</code>或者<code>对象</code>,如:</li></ul><p><img src="/c/assets/16.D74t3-Xt.png" alt=""></p><ul><li>根据<code>操作数</code>的<code>个数</code>,可以将运算符分为: <ul><li>一元运算符(一目运算符)。</li><li>二元运算符(二目运算符)。</li><li>三元运算符(三目运算符)。</li></ul></li><li>根据<code>功能</code>,可以将运算符分为: <ul><li>算术运算符。</li><li>关系运算符(比较运算符)。</li><li>逻辑运算符。</li><li>赋值运算符。</li><li>逻辑运算符。</li><li>位运算符。</li><li>三元运算符。</li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>掌握一个运算符,需要关注以下几个方面:</p><ul><li>① 运算符的含义。</li><li>② 运算符操作数的个数。</li><li>③ 运算符所组成的表达式。</li><li>④ 运算符有无副作用,即:运算后是否会修改操作数的值。</li></ul></div><h2 id="_2-2-算术运算符" tabindex="-1">2.2 算术运算符 <a class="header-anchor" href="#_2-2-算术运算符" aria-label="Permalink to "2.2 算术运算符""></a></h2><ul><li>算术运算符是对数值类型的变量进行运算的,如下所示:</li></ul><table tabindex="0"><thead><tr><th>运算符</th><th>描述</th><th>操作数个数</th><th>组成的表达式的值</th><th>副作用</th></tr></thead><tbody><tr><td><code>+</code></td><td>正号</td><td>1</td><td>操作数本身</td><td>❎</td></tr><tr><td><code>-</code></td><td>负号</td><td>1</td><td>操作数符号取反</td><td>❎</td></tr><tr><td><code>+</code></td><td>加号</td><td>2</td><td>两个操作数之和</td><td>❎</td></tr><tr><td><code>-</code></td><td>减号</td><td>2</td><td>两个操作数之差</td><td>❎</td></tr><tr><td><code>*</code></td><td>乘号</td><td>2</td><td>两个操作数之积</td><td>❎</td></tr><tr><td><code>/</code></td><td>除号</td><td>2</td><td>两个操作数之商</td><td>❎</td></tr><tr><td><code>%</code></td><td>取模(取余)</td><td>2</td><td>两个操作数相除的余数</td><td>❎</td></tr><tr><td><code>++</code></td><td>自增</td><td>1</td><td>操作数自增前或自增后的值</td><td>✅</td></tr><tr><td><code>--</code></td><td>自减</td><td>1</td><td>操作数自减前或自减后的值</td><td>✅</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>自增和自减:</p><ul><li>① 自增、自减运算符可以写在操作数的前面也可以写在操作数后面,不论前面还是后面,对操作数的副作用是一致的。</li><li>② 自增、自减运算符在前在后,对于表达式的值是不同的。 如果运算符在前,表达式的值是操作数自增、自减之后的值;如果运算符在后,表达式的值是操作数自增、自减之前的值。</li><li>③ <code>变量前++</code>:变量先自增 1 ,然后再运算;<code>变量后++</code>:变量先运算,然后再自增 1 。</li><li>④ <code>变量前--</code>:变量先自减 1 ,然后再运算;<code>变量后--</code>:变量先运算,然后再自减 1 。</li></ul></div><ul><li>示例:正号和负号</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> <stdio.h></span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 12</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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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;"> x1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">x, x2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> +</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">x;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> y </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">67</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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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;"> y1 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> -</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">y, y2 </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> +</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">y;</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, y1, y2);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // y1=67, y2=-67</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><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;"> <stdio.h></span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 5</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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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;"> 2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"</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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"</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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"</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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"</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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a, b, a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">%</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 5 % 2 = 1</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><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;"> <stdio.h></span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, res1);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 10 % 3 = 1</span></span>
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<span class="line"></span>
|
||
<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;">"-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;">"</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;">"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;">"</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;">"-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;">"</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;"> <stdio.h></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;">"i = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"i1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"i = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"i1 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"i = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"i2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"i = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"i2 = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;"> <stdio.h></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;">"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;">"</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;">"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;">"</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;">"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;">"</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 "2.3 关系运算符(比较运算符)""></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><</code></td><td>小于</td><td>2</td><td>0 或 1</td><td>❎</td></tr><tr><td><code>></code></td><td>大于</td><td>2</td><td>0 或 1</td><td>❎</td></tr><tr><td><code><=</code></td><td>小于等于</td><td>2</td><td>0 或 1</td><td>❎</td></tr><tr><td><code>>=</code></td><td>大于等于</td><td>2</td><td>0 或 1</td><td>❎</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① C 语言中,没有严格意义上的布尔类型,所以可以 0(假) 或 1(真)表示布尔类型的值。</li><li>② 不要将 <code>==</code> 写成 <code>=</code>,<code>==</code> 是比较运算符,而 <code>=</code> 是赋值运算符。</li><li>③ <code>>=</code> 或 <code><=</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;"> <stdio.h></span></span>
|
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<span class="line"></span>
|
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
|
||
<span class="line"></span>
|
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 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>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</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 style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</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 style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</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>
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||
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</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;">"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;">"</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>
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||
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</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>
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||
<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>
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||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><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 "2.4 逻辑运算符""></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>&&</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 && b</th><th>a || b</th><th>!a</th></tr></thead><tbody><tr><td>1(真)</td><td>1(真)</td><td>1(真)</td><td>1(真)</td><td>0(假)</td></tr><tr><td>1(真)</td><td>0(假)</td><td>0(假)</td><td>1(真)</td><td>0(假)</td></tr><tr><td>0(假)</td><td>1(真)</td><td>0(假)</td><td>1(真)</td><td>1(真)</td></tr><tr><td>0(假)</td><td>0(假)</td><td>0(假)</td><td>0(假)</td><td>1(真)</td></tr></tbody></table><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 对于逻辑运算符来说,任何非零值都表示真,零值表示假,如:<code>5 || 0</code> 返回 <code>1</code> ,<code>5 && 0</code> 返回 <code>0</code> 。</li><li>② 短路现象: <ul><li>对于 <code>a && b</code> 操作来说,当 a 为假(或 0 )时,因为 <code>a && 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;"> <stdio.h></span></span>
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||
<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>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"请输入整数a的值:"</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;">"</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">a);</span></span>
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||
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"请输入整数b的值:"</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;">"</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">b);</span></span>
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||
<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;">></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;">"</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:#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;"><</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b) {</span></span>
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||
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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:#24292E;--shiki-dark:#E1E4E8;">, a, b);</span></span>
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||
<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;">"</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:#24292E;--shiki-dark:#E1E4E8;">, a, b);</span></span>
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||
<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;"> <stdio.h></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;">&&</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;"> ></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;">"床前明月光</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"我叫郭德纲</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"</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;">"</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;"> <stdio.h></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;"> ></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;">"床前明月光 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"我叫郭德纲 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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 "2.5 赋值运算符""></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><<=</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>>>=</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>&=</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;"> <stdio.h></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;">"a = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, a);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // a = 6</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> b </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">-=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // b = b - 3</span></span>
|
||
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"b = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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;">"c = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, c);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // c = 9</span></span>
|
||
<span class="line"></span>
|
||
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
|
||
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> d </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">/=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // d = d / 3</span></span>
|
||
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"d = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</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>
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<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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"e = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, e);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // e = 0</span></span>
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<span class="line"></span>
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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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><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 "2.6 位运算符(了解)""></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 "2.6.1 概述""></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>&</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><<</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>>></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 "2.6.2 输出二进制位""></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;"> <stdio.h></span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">/**</span></span>
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<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>
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<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>
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<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 '0b' 字符</span></span>
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<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> */</span></span>
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<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>
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<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>
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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;"> i, j;</span></span>
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<span class="line"></span>
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<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;">>=</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>
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<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;">>></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>
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<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;"> '0'</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
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<span class="line"></span>
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<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;"> '</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\0</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">'</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> binaryString;</span></span>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> a </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 17</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 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>
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<span class="line"></span>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"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;">"</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>
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<span class="line"></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>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><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 "2.6.3 按位与""></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都是 1 才是 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>0</code> 。</li><li><code>0 & 1</code> 的结果是 <code>0</code> 。</li><li><code>0 & 0</code> 的结果是 <code>0</code> 。</li></ul></li><li><p>示例:<code>9 & 7 = 1</code></p></li></ul><p><img src="/c/assets/17.DdAZIfeP.png" alt=""></p><ul><li>示例:<code>-9 & 7 = 7</code></li></ul><p><img src="/c/assets/18.B4Zfj2jX.png" alt=""></p><h3 id="_2-6-4-按位或" tabindex="-1">2.6.4 按位或 <a class="header-anchor" href="#_2-6-4-按位或" aria-label="Permalink to "2.6.4 按位或""></a></h3><ul><li><p>按位与 <code>|</code> 的运算规则是:如果二进制对应的位上只要有 1 就是 1 ,否则为 0 ,即:</p><ul><li><code>1 | 1</code> 的结果是 <code>1</code> 。</li><li><code>1 | 0</code> 的结果是 <code>1</code> 。</li><li><code>0 | 1</code> 的结果是 <code>1</code> 。</li><li><code>0 | 0</code> 的结果是 <code>0</code> 。</li></ul></li><li><p>示例:<code>9 | 7 = 15</code></p></li></ul><p><img src="/c/assets/19.IfpA0D5n.png" alt=""></p><ul><li>示例:<code>-9 | 7 = -9</code></li></ul><p><img src="/c/assets/20.CfIzYazX.png" alt=""></p><h3 id="_2-6-5-按位异或" tabindex="-1">2.6.5 按位异或 <a class="header-anchor" href="#_2-6-5-按位异或" aria-label="Permalink to "2.6.5 按位异或""></a></h3><ul><li>按位与 <code>^</code> 的运算规则是:如果二进制对应的位上一个为 1 一个为 0 就为 1 ,否则为 0 ,即: <ul><li><code>1 ^ 1</code> 的结果是 <code>0</code> 。</li><li><code>1 ^ 0</code> 的结果是 <code>1</code> 。</li><li><code>0 ^ 1</code> 的结果是 <code>1</code> 。</li><li><code>0 ^ 0</code> 的结果是 <code>0</code> 。</li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>按位异或的场景有:</p><ul><li>① 交换两个数值:异或操作可以在不使用临时变量的情况下交换两个变量的值。</li><li>② 加密或解密:异或操作用于简单的加密和解密算法。</li><li>③ 错误检测和校正:异或操作可以用于奇偶校验位的计算和检测错误(RAID-3 以及以上)。</li><li>……</li></ul></div><ul><li>示例:<code>9 ^ 7 = 14</code></li></ul><p><img src="/c/assets/21.eHnZcbpI.png" alt=""></p><ul><li>示例:<code>-9 ^ 7 = -16</code></li></ul><p><img src="/c/assets/22.BNoKlM4o.png" alt=""></p><h3 id="_2-6-6-按位取反" tabindex="-1">2.6.6 按位取反 <a class="header-anchor" href="#_2-6-6-按位取反" aria-label="Permalink to "2.6.6 按位取反""></a></h3><ul><li><p>运算规则:如果二进制对应的位上是 1,则结果为 0;如果是 0 ,则结果为 1 。</p><ul><li><code>~0</code> 的结果是 <code>1</code> 。</li><li><code>~1</code> 的结果是 <code>0</code> 。</li></ul></li><li><p>示例:<code>~9 = -10</code></p></li></ul><p><img src="/c/assets/23.CMVtwrqr.png" alt=""></p><ul><li>示例:<code>~-9 = 8</code></li></ul><p><img src="/c/assets/24.CN19KJG7.png" alt=""></p><h3 id="_2-6-7-二进制左移" tabindex="-1">2.6.7 二进制左移 <a class="header-anchor" href="#_2-6-7-二进制左移" aria-label="Permalink to "2.6.7 二进制左移""></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 << 4 = 48</code> (3 × 2^4)</p></li></ul><p><img src="/c/assets/25.BIhiJHjz.png" alt=""></p><ul><li>示例:<code>-3 << 4 = -48</code> (-3 × 2 ^4)</li></ul><p><img src="/c/assets/26.A_E4n4g8.png" alt=""></p><h3 id="_2-6-7-二进制右移" tabindex="-1">2.6.7 二进制右移 <a class="header-anchor" href="#_2-6-7-二进制右移" aria-label="Permalink to "2.6.7 二进制右移""></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 >> 4 = 4</code> (69 ÷ 2^4 )</li></ul><p><img src="/c/assets/27.Bv4qFbwF.png" alt=""></p><ul><li>示例:<code>-69 >> 4 = -5</code> (-69 ÷ 2^4 )</li></ul><p><img src="/c/assets/28.IKaazo2J.png" alt=""></p><h2 id="_2-7-三元运算符" tabindex="-1">2.7 三元运算符 <a class="header-anchor" href="#_2-7-三元运算符" aria-label="Permalink to "2.7 三元运算符""></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;"> <stdio.h></span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 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>
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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;"> 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>
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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;"> 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;">></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>
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<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"result = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">"</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, result);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // result = 110</span></span>
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<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
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<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></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 "2.8 运算符优先级""></a></h2><ul><li>C 语言中运算符的优先级,如下所示:</li></ul><table tabindex="0"><thead><tr><th><strong>优先级</strong></th><th><strong>运算符</strong></th><th><strong>名称或含义</strong></th><th><strong>结合方向</strong></th></tr></thead><tbody><tr><td><strong>1</strong></td><td><code>[]</code></td><td>数组下标</td><td>左到右</td></tr><tr><td></td><td><code>()</code></td><td>圆括号</td><td></td></tr><tr><td></td><td><code>.</code></td><td>成员选择(对象)</td><td></td></tr><tr><td></td><td><code>-></code></td><td>成员选择(指针)</td><td></td></tr><tr><td><strong>2</strong></td><td><code>-</code></td><td>负号运算符</td><td>右到左</td></tr><tr><td></td><td><code>(类型)</code></td><td>强制类型转换</td><td></td></tr><tr><td></td><td><code>++</code></td><td>自增运算符</td><td></td></tr><tr><td></td><td><code>--</code></td><td>自减运算符</td><td></td></tr><tr><td></td><td><code>*</code></td><td>取值运算符</td><td></td></tr><tr><td></td><td><code>&</code></td><td>取地址运算符</td><td></td></tr><tr><td></td><td><code>!</code></td><td>逻辑非运算符</td><td></td></tr><tr><td></td><td><code>~</code></td><td>按位取反运算符</td><td></td></tr><tr><td></td><td><code>sizeof</code></td><td>长度运算符</td><td></td></tr><tr><td><strong>3</strong></td><td><code>/</code></td><td>除</td><td>左到右</td></tr><tr><td></td><td><code>*</code></td><td>乘</td><td></td></tr><tr><td></td><td><code>%</code></td><td>余数(取模)</td><td></td></tr><tr><td><strong>4</strong></td><td><code>+</code></td><td>加</td><td>左到右</td></tr><tr><td></td><td><code>-</code></td><td>减</td><td></td></tr><tr><td><strong>5</strong></td><td><code><<</code></td><td>左移</td><td>左到右</td></tr><tr><td></td><td><code>>></code></td><td>右移</td><td></td></tr><tr><td><strong>6</strong></td><td><code>></code></td><td>大于</td><td>左到右</td></tr><tr><td></td><td><code>>=</code></td><td>大于等于</td><td></td></tr><tr><td></td><td><code><</code></td><td>小于</td><td></td></tr><tr><td></td><td><code><=</code></td><td>小于等于</td><td></td></tr><tr><td><strong>7</strong></td><td><code>==</code></td><td>等于</td><td>左到右</td></tr><tr><td></td><td><code>!=</code></td><td>不等于</td><td></td></tr><tr><td><strong>8</strong></td><td><code>&</code></td><td>按位与</td><td>左到右</td></tr><tr><td><strong>9</strong></td><td><code>^</code></td><td>按位异或</td><td>左到右</td></tr><tr><td><strong>10</strong></td><td><code>|</code></td><td>按位或</td><td>左到右</td></tr><tr><td><strong>11</strong></td><td><code>&&</code></td><td>逻辑与</td><td>左到右</td></tr><tr><td><strong>12</strong></td><td><code>||</code></td><td>逻辑或</td><td>左到右</td></tr><tr><td><strong>13</strong></td><td><code>?:</code></td><td>条件运算符</td><td>右到左</td></tr><tr><td><strong>14</strong></td><td><code>=</code></td><td>赋值运算符</td><td>右到左</td></tr><tr><td></td><td><code>/=</code></td><td>除后赋值</td><td></td></tr><tr><td></td><td><code>*=</code></td><td>乘后赋值</td><td></td></tr><tr><td></td><td><code>%=</code></td><td>取模后赋值</td><td></td></tr><tr><td></td><td><code>+=</code></td><td>加后赋值</td><td></td></tr><tr><td></td><td><code>-=</code></td><td>减后赋值</td><td></td></tr><tr><td></td><td><code><<=</code></td><td>左移后赋值</td><td></td></tr><tr><td></td><td><code>>>=</code></td><td>右移后赋值</td><td></td></tr><tr><td></td><td><code>&=</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>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 > 算术运算符 > 关系运算符 > 逻辑运算符 > 三元运算符 > 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 "第三章:附录""></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 "3.1 字符集和字符集编码""></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 "3.3.1 概述""></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>"A"</code>在ASCII 编码中表示为二进制的<code>1000001</code>,十进制的 <code>65</code> 。</p></div><ul><li><code>字符集</code>和<code>字符集编码</code>之间的关系如下:</li></ul><p><img src="/c/assets/29.CGTVELeO.png" alt=""></p><ul><li>Linux 中安装帮助手册:</li></ul><p><img src="/c/assets/30.Bz4_lEH0.gif" alt=""></p><h3 id="_3-3-2-ascii-编码" tabindex="-1">3.3.2 ASCII 编码 <a class="header-anchor" href="#_3-3-2-ascii-编码" aria-label="Permalink to "3.3.2 ASCII 编码""></a></h3><ul><li>从<code>冯·诺依曼</code>体系结构中,我们知道,计算机中所有的<code>数据</code>和<code>指令</code>都是以<code>二进制</code>的形式表示的;所以,计算机中对于文本数据的数据也是以二进制来存储的,那么对应的流程如下:</li></ul><p><img src="/c/assets/31.CcDWE4nn.png" alt=""></p><ul><li>我们知道,计算机是上个世纪 60 年代在美国研制成功的,为了实现字符和二进制的转换,美国就制定了一套字符编码,即英语字符和二进制位之间的关系,即 ASCII (American Standard Code for Information Interchange)编码: <ul><li>ASCII 编码只包括了英文字符、数字和一些特殊字符,一共 128 个字符,并且每个字符都分配了唯一的数字,范围是 0 - 127。</li><li>ASCII 编码中的每个字符都使用 7 位的二进制数字表示;但是,计算机中的存储的最小单位是 1 B = 8 位,那么最高位统一规定为 0 。</li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 其实,早期是没有字符集的概念的,只是后来为了解决乱码问题,而产生了字符集的概念。</li><li>② 对于英文体系来说,<code>a-zA-Z0-9</code>以及一些<code>特殊字符</code>一共 <code>128</code> 就可以满足实际存储需求;所以,在也是为什么 ASCII 码使用 7 位二进制(2^7 = 128 )来存储的。</li></ul></div><ul><li>在操作系统中,就内置了对应的编码表,Linux 也不例外;可以使用如下的命令查看:</li></ul><div class="language-shell vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">shell</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">man</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> ascii</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><p><img src="/c/assets/32.B7y2_JVX.gif" alt=""></p><ul><li>其对应的 ASCII 编码表,如下所示:</li></ul><p><img src="/c/assets/33.Btcc3rs2.gif" alt=""></p><ul><li>但是,随着计算机的发展,计算机开始了东征之路,由美国传播到东方:</li></ul><p><img src="/c/assets/34.CR4ARW8y.png" alt=""></p><ul><li>先是传播到了欧洲,欧洲在兼容 ASCII 编码的基础上,推出了 ISO8859-1 编码,即: <ul><li>ISO8859-1 编码包括基本的拉丁字母表、数字、标点符号,以及西欧语言中特有的一些字符,如:法语中的 <code>è</code>、德语中的 <code>ü</code> 等。</li><li>ISO 8859-1 为每个字符分配一个单字节(8 位)编码,意味着它可以表示最多 256 (2^8)个不同的字符(编号从 0 到 255)。</li><li>ISO 8859-1 的前 128 个字符与 ASCII 编码完全一致,这使得 ASCII 编码的文本可以无缝转换为 ISO 8859-1 编码。</li></ul></li></ul><p><img src="/c/assets/33.Btcc3rs2.gif" alt=""></p><p><img src="/c/assets/36.DOX3ymYP.gif" alt=""></p><ul><li>计算机继续传播到了亚洲,亚洲(双字节)各个国家分别给出了自己国家对应的字符集编码,如: <ul><li>日本推出了 Shift-JIS 编码: <ul><li>单字节 ASCII 范围:0 - 127。</li><li>双字节范围: <ul><li>第一个字节:129 - 159 和 224 - 239 。</li><li>第二个字节:64 - 126 和 128 - 252 。</li></ul></li></ul></li><li>韩国推出了 EUC-KR 编码: <ul><li>单字节 ASCII 范围:0 - 127。</li><li>双字节范围:从 41281 - 65278。</li></ul></li><li>中国推出了 GBK 编码: <ul><li>单字节 ASCII 范围:0 - 127。</li><li>双字节范围:33088 - 65278 。</li></ul></li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 通过上面日本、韩国、中国的编码十进制范围,我们可以看到,虽然这些编码系统在技术上的编码范围存在重叠(特别是在高位字节区域),但因为它们各自支持的字符集完全不同,所以实际上它们并不直接冲突。</li><li>② 但是,如果一个中国人通过 GBK 编码写的文章,通过邮件发送给韩国人,因为韩国和中国在字符集编码上的高位字节有重叠部分,必然会造成歧义。</li></ul></div><h3 id="_3-3-3-unicode-编码" tabindex="-1">3.3.3 Unicode 编码 <a class="header-anchor" href="#_3-3-3-unicode-编码" aria-label="Permalink to "3.3.3 Unicode 编码""></a></h3><ul><li><p>在 Unicode 之前,世界上存在着数百种不同的编码系统,每一种编码系统都是为了支持特定语言或一组语言的字符集。这些编码系统,包括:ASCII、ISO 8859 系列、GBK、Shift-JIS、EUC-KR 等,它们各自有不同的字符范围和编码方式。这种多样性虽然在局部范围内解决了字符表示的问题,但也带来了以下几个方面的挑战:</p><ul><li><code>编码冲突</code>:由于不同的编码系统可以为相同的字节值分配不同的字符,因此在不同编码之间转换文本时,如果没有正确处理编码信息,就很容易产生乱码。这种编码冲突在尝试处理多种语言的文本时尤为突出。</li><li><code>编码的复杂性</code>:随着全球化的发展,软件和系统需要支持越来越多的语言,这就要求开发者和系统同时处理多种不同的编码系统。这不仅增加了开发和维护的复杂性,而且也增加了出错的风险。</li><li><code>资源限制</code>:在早期计算机技术中,内存和存储资源相对有限。不同的编码标准要求系统存储多套字符集数据,这无疑增加了对有限资源的消耗。</li><li>……</li></ul></li><li><p>针对上述的种种问题,为了推行全球化,Unicode 应运而生,Unicode 的核心规则和设计原则是建立一个全球统一的字符集,使得世界上所有的文字和符号都能被唯一地识别和使用,无论使用者位于何地或使用何种语言。这套规则包括了字符的编码、表示、处理和转换机制,旨在确保不同系统和软件间能够无缝交换和处理文本数据。</p><ul><li><code>通用字符集 (UCS)</code>:Unicode 为每一个字符分配一个唯一的编号(称为<code>“码点”</code>)。这些码点被组织在一个统一的字符集中,官方称之为 “通用字符集”(Universal Character Set,UCS)。码点通常表示为 <code>U+</code> 后跟一个十六进制数,例如:<code>U+0041</code> 代表大写的英文字母 <code>“A”</code>。</li><li><code>编码平面和区段</code>:Unicode 码点被划分为多个 “平面(Planes)”,每个平面包含 65536(16^4)个码点。目前,Unicode定义了 17 个平面(从 0 到16),每个平面被分配了一个编号,从 “基本多文种平面(BMP)” 的 0 开始,到 16 号平面结束。这意味着 Unicode 理论上可以支持超过 110万(17*65536)个码点。</li></ul></li><li><p>Unicode 仅仅只是字符集,给每个字符设置了唯一的数字编号而已,却没有给出这些数字编号实际如何存储,可以通过如下命令查看:</p></li></ul><p><img src="/c/assets/37.Cie9_tkP.gif" alt=""></p><ul><li>为了在计算机系统中表示 Unicode 字符,定义了几种编码方案,这些方案包括 UTF-8、UTF-16 和 UTF-32 等。 <ul><li><strong>UTF-8</strong>:使用 1 - 4 个字节表示每个 Unicode 字符,兼容 ASCII,是网络上最常用的编码。</li><li><strong>UTF-16</strong>:使用 2 - 4 个字节表示每个 Unicode 字符,适合于需要经常处理基本多文种平面之外字符的应用。</li><li><strong>UTF-32</strong>:使用固定的 4 个字节表示每个 Unicode 字符,简化了字符处理,但增加了存储空间的需求。</li></ul></li><li><code>Unicode 字符集</code>和对应的<code>UTF-8 字符编码</code>之间的关系,如下所示:</li></ul><p><img src="/c/assets/38.DLjH9Ges.png" alt=""></p></div></div></main><footer class="VPDocFooter" data-v-39a288b8 data-v-d4a0bba5><!--[--><!--]--><div class="edit-info" data-v-d4a0bba5><!----><div class="last-updated" data-v-d4a0bba5><p class="VPLastUpdated" data-v-d4a0bba5 data-v-7e05ebdb>上次更新: <time datetime="2024-07-19T08:20:18.000Z" 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