Aexiar/c
1
0
Fork 0
mirror of https://github.com/Aexiar/c.git synced 2024-10-22 14:05:45 +02:00
Code Issues Packages Projects Releases Wiki Activity
7e266002ac
c/assets/notes_01_c-basic_04_xdx_index.md.DHqdsloC.js
Aurorxa fbbed3d647 deploy: 8b2982b93e
2024-08-15 03:48:49 +00:00

753 lines
280 KiB
JavaScript
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

import{_ as l,c as a,j as s,a6 as i,o as n}from"./chunks/framework.CZRoMP2i.js";const p="/c/assets/1.CTMA-Poz.jpg",h="/c/assets/2.B2g4y1OY.png",k="/c/assets/3.DEoM0p3m.png",t="/c/assets/4.DxEoA7Ht.png",e="/c/assets/5.DtY5Pf6u.png",r="/c/assets/6.CButBugT.png",E="/c/assets/7.DG_I9X5w.png",d="/c/assets/8.Cw8LCRHN.png",g="/c/assets/9.TqkSPw2X.png",c="/c/assets/10.DJkVOkw7.png",y="/c/assets/11.Bkdbe2NL.png",F="/c/assets/12.D2yeCvfw.png",H=JSON.parse('{"title":"第一章：概述","description":"","frontmatter":{},"headers":[],"relativePath":"notes/01_c-basic/04_xdx/index.md","filePath":"notes/01_c-basic/04_xdx/index.md","lastUpdated":1722933158000}'),b={name:"notes/01_c-basic/04_xdx/index.md"},u=i('<h1 id="第一章-概述" tabindex="-1">第一章：概述 <a class="header-anchor" href="#第一章-概述" aria-label="Permalink to &quot;第一章：概述&quot;">​</a></h1><ul><li><p><code>流程控制结构</code>是用来控制程序中<code>各语句执行顺序</code>的语句，并且可以将语句组合成能<code>完成一定功能</code>的<code>小逻辑模块</code>。</p></li><li><p>在程序设计中规定了<code>三种</code>流程结构，如下所示：</p><ul><li><code>顺序结构</code>：程序从上到下逐行执行，中间没有任何判断和跳转。</li><li><code>分支结构</code>：根据条件，有选择的执行某段代码。在 C 语言中，有 <code>if...else</code> 和 <code>switch...case</code> 两种分支语句。</li><li><code>循环结构</code>：根据循环条件，重复性的执行某段代码。在 C 语言中，有 <code>for</code>、<code>while</code>、<code>do...while</code> 三种循环结构。</li></ul></li><li><p>在生活中的<code>洗衣工厂</code>，就包含了上述的三种流程结构，如下所示：</p></li></ul><p><img src="'+p+'" alt="" loading="lazy"></p><h1 id="第二章-顺序结构" tabindex="-1">第二章：顺序结构 <a class="header-anchor" href="#第二章-顺序结构" aria-label="Permalink to &quot;第二章：顺序结构&quot;">​</a></h1><h2 id="_2-1-概述" tabindex="-1">2.1 概述 <a class="header-anchor" href="#_2-1-概述" aria-label="Permalink to &quot;2.1 概述&quot;">​</a></h2><ul><li>程序从上到下逐行地执行，表达式语句都是顺序执行的，并且上一行对某个变量的修改对下一行会产生影响。</li></ul><p><img src="'+h+`" alt="" loading="lazy"></p><h2 id="_2-2-应用示例" tabindex="-1">2.2 应用示例 <a class="header-anchor" href="#_2-2-应用示例" aria-label="Permalink to &quot;2.2 应用示例&quot;">​</a></h2><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </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;"> y </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;x = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, x);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // x = 1</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;y = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, y);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // y = 2</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 对 x 和 y 的值进行修改</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x</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:#24292E;--shiki-dark:#E1E4E8;"> y </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 2</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> *</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> y;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> x </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</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>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;x = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, x);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // x = 20</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;y = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, y);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // y = 6</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><h1 id="第三章-分支结构-⭐" tabindex="-1">第三章：分支结构（⭐） <a class="header-anchor" href="#第三章-分支结构-⭐" aria-label="Permalink to &quot;第三章：分支结构（⭐）&quot;">​</a></h1><h2 id="_3-1-概述" tabindex="-1">3.1 概述 <a class="header-anchor" href="#_3-1-概述" aria-label="Permalink to &quot;3.1 概述&quot;">​</a></h2><ul><li>根据特定条件执行不同的代码块，从而实现灵活的程序控制和更复杂的逻辑。</li></ul><h2 id="_3-2-单分支结构" tabindex="-1">3.2 单分支结构 <a class="header-anchor" href="#_3-2-单分支结构" aria-label="Permalink to &quot;3.2 单分支结构&quot;">​</a></h2><h3 id="_3-2-1-概述" tabindex="-1">3.2.1 概述 <a class="header-anchor" href="#_3-2-1-概述" aria-label="Permalink to &quot;3.2.1 概述&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(条件表达式){</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 语句;</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></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 在 C 语言中，严格意义上是没有 boolean 类型的，使用<code>非0</code> 表示<code>真（true）</code>，<code>0</code> 表示<code>假（false）</code>。</li><li>② 当条件表达式为真（<code>非0</code> ），就会执行代码块中的语句；否则，就不会执行代码块中的语句。</li></ul></div><ul><li>流程图，如下所示：</li></ul><p><img src="`+k+`" alt="" loading="lazy"></p><h3 id="_3-2-2-应用示例" tabindex="-1">3.2.2 应用示例 <a class="header-anchor" href="#_3-2-2-应用示例" aria-label="Permalink to &quot;3.2.2 应用示例&quot;">​</a></h3><ul><li><p>需求：成年人心率的正常范围是每分钟 60~100 次。体检时，如果心率不在此范围内，则提示需要做进一步的检查。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> heartBeats </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入您的心率：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">heartBeats);</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;"> (heartBeats </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 60</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> ||</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> heartBeats </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;您的心率不在正常范围内，请做进一步的检查。</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;体检结束！！！&quot;</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;"> 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="_3-2-3-应用示例" tabindex="-1">3.2.3 应用示例 <a class="header-anchor" href="#_3-2-3-应用示例" aria-label="Permalink to &quot;3.2.3 应用示例&quot;">​</a></h3><ul><li><p>需求：根据年龄判断，如果是未成年人，则提示 &quot;未成年人请在家长陪同下访问！&quot; 。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> age </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入你的年龄：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">age);</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;"> (age </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 18</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;未成年人请在家长陪同下访问！</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;欢迎继续访问！&quot;</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;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br></div></div><h2 id="_3-3-双分支结构" tabindex="-1">3.3 双分支结构 <a class="header-anchor" href="#_3-3-双分支结构" aria-label="Permalink to &quot;3.3 双分支结构&quot;">​</a></h2><h3 id="_3-3-1-概述" tabindex="-1">3.3.1 概述 <a class="header-anchor" href="#_3-3-1-概述" aria-label="Permalink to &quot;3.3.1 概述&quot;">​</a></h3><ul><li>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;">if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(条件表达式) { </span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 语句块1;</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:#24292E;--shiki-dark:#E1E4E8;"> 语句块2;</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></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 在 C 语言中，严格意义上是没有 boolean 类型的，使用<code>非0</code> 表示<code>真（true）</code>，<code>0</code> 表示<code>假（false）</code>。</li><li>② 当条件表达式为真（<code>非0</code> ），就会执行代码块 1 中的语句；否则，执行代码块 2 中的语句。</li></ul></div><ul><li>流程图，如下所示：</li></ul><p><img src="`+t+`" alt="" loading="lazy"></p><h3 id="_3-3-2-应用示例" tabindex="-1">3.3.2 应用示例 <a class="header-anchor" href="#_3-3-2-应用示例" aria-label="Permalink to &quot;3.3.2 应用示例&quot;">​</a></h3><ul><li><p>需求：判断一个整数，是奇数还是偶数。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> 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;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入一个整数：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">num);</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;"> (num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">%</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 2</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> ==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 是偶数</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 是奇数</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num);</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></div></div><h3 id="_3-3-2-应用示例-1" tabindex="-1">3.3.2 应用示例 <a class="header-anchor" href="#_3-3-2-应用示例-1" aria-label="Permalink to &quot;3.3.2 应用示例&quot;">​</a></h3><ul><li><p>需求：输入年龄，如果大于18岁，则输出 &quot;你年龄大于18，要对自己的行为负责!&quot;；否则，输出 &quot;你的年龄不大这次放过你了。&quot;</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> age </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入年龄：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">age);</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;"> (age </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 18</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你年龄大于18，要对自己的行为负责!</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你的年龄不大，这次放过你了!</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<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="_3-3-3-应用示例" tabindex="-1">3.3.3 应用示例 <a class="header-anchor" href="#_3-3-3-应用示例" aria-label="Permalink to &quot;3.3.3 应用示例&quot;">​</a></h3><ul><li>需求：判定某个年份是否为闰年？</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① year 是 400 的整倍数： year%400==0</li><li>② 能被 4 整除，但不能被 100 整除：year % 4 == 0 &amp;&amp; year % 100 != 0</li></ul></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> year </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入年份：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">year);</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;"> (year </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">%</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 400</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:#24292E;--shiki-dark:#E1E4E8;"> (year </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">%</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 4</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;"> &amp;&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> year </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;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 是闰年</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, year);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 不是闰年</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, year);</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></div></div><h2 id="_3-4-多重分支结构" tabindex="-1">3.4 多重分支结构 <a class="header-anchor" href="#_3-4-多重分支结构" aria-label="Permalink to &quot;3.4 多重分支结构&quot;">​</a></h2><h3 id="_3-4-1-概述" tabindex="-1">3.4.1 概述 <a class="header-anchor" href="#_3-4-1-概述" aria-label="Permalink to &quot;3.4.1 概述&quot;">​</a></h3><ul><li>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;">if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (条件表达式1) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 语句块1;</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;"> (条件表达式2) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 语句块2;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">...</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;"> (条件表达式n) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 语句块n;</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:#24292E;--shiki-dark:#E1E4E8;"> 语句块n</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:#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><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 在 C 语言中，严格意义上是没有 boolean 类型的，使用<code>非0</code> 表示<code>真（true）</code>，<code>0</code> 表示<code>假（false）</code>。</li><li>② 首先判断关系表达式 1 的结果是真（值为 <code>非0</code>）还是假（值为 <code>0</code>）： <ul><li>如果为真，就执行语句块 1，然后结束当前多分支。</li><li>如果是假，就继续判断条件表达式 2，看其结果是真还是假。</li><li>如果是真，就执行语句块 2，然后结束当前多分支。</li><li>如果是假，就继续判断条件表达式…看其结果是真还是假。</li><li>...</li><li>如果没有任何关系表达式为真，就执行语句块 n+1，然后结束当前多分支。</li></ul></li><li>③ 当条件表达式之间是<code>互斥</code>（彼此之间没有交集）关系时，条件判断语句及执行语句间顺序无所谓。</li><li>④ 当条件表达式之间是<code>包含</code>关系时，必须<code>小上大下 / 子上父下</code>，否则范围小的条件表达式将不可能被执行。</li><li>⑤ 当 if-else 结构是多选一的时候，最后的 else 是可选的，可以根据需要省略。</li><li>⑥ 如果语句块中只有一条执行语句的时候，<code>{}</code>是可以省略的；但是，强烈建议保留！！！</li></ul></div><ul><li>流程图，如下所示：</li></ul><p><img src="`+e+`" alt="image-20240722075241253" loading="lazy"></p><h3 id="_3-4-1-应用示例" tabindex="-1">3.4.1 应用示例 <a class="header-anchor" href="#_3-4-1-应用示例" aria-label="Permalink to &quot;3.4.1 应用示例&quot;">​</a></h3><ul><li><p>需求：张三参加考试，他和父亲达成协议，如果成绩不到 60 分没有任何奖励；如果成绩 60分（含）到 80 分，奖励一个肉夹馍；如果成绩 80 分（含）到 90 分，奖励一个 ipad；如果成绩 90 分及以上，奖励一部华为 mate60 pro 。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> score </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入分数：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">score);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 容错：分数不可能小于 0 或大于 100</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (score </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> ||</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> score </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;输入的分数有误！</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 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>
<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;"> (score </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 90</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;奖励你一部华为 mate60 pro</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (score </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 80</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;奖励你一个 ipad</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (score </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 60</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;奖励你一个肉夹馍</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;你的成绩不及格，没有任何奖励！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br></div></div><h3 id="_3-4-2-应用示例" tabindex="-1">3.4.2 应用示例 <a class="header-anchor" href="#_3-4-2-应用示例" aria-label="Permalink to &quot;3.4.2 应用示例&quot;">​</a></h3><ul><li><p>需求：判断水的温度，如果大于 95℃，则打印 &quot;开水&quot;；如果大于 70℃ 且小于等于 95℃，则打印 &quot;热水&quot;；如果大于 40℃ 且小于等于 70℃，则打印 &quot;温水&quot;；如果小于等于 40℃，则打印 &quot;凉水&quot;。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> temperature </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入水的温度：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">temperature);</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;"> (temperature </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 95</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;开水 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (temperature </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 70</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> &amp;&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> temperature </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 95</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;热水 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (temperature </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 40</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> &amp;&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> temperature </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 70</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;温水 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;凉水 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<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></div></div><h2 id="_3-5-多重分支结构-switch" tabindex="-1">3.5 多重分支结构 switch <a class="header-anchor" href="#_3-5-多重分支结构-switch" aria-label="Permalink to &quot;3.5 多重分支结构 switch&quot;">​</a></h2><h3 id="_3-5-1-概述" tabindex="-1">3.5.1 概述 <a class="header-anchor" href="#_3-5-1-概述" aria-label="Permalink to &quot;3.5.1 概述&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">switch</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(表达式){</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 常量值1: </span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 语句块1;</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> //break;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 常量值2: </span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 语句块2;</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> //break;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ...</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> </span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 常量值n: </span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 语句块n; </span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> //break;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> [default: </span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 语句块n</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:#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><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① switch 后面表达式的值必须是一个整型（char、short、int、long 等）或枚举类型。</li><li>② case 后面的值必须是常量，不能是变量。</li><li>③ default 是可选的，当没有匹配的 case 的时候，就执行 default 。</li><li>④ break 语句可以使程序跳出 switch 语句块，如果没有 break，会执行下一个 case 语句块，直到遇到 break 或者执行到 switch 结尾，这个现象称为穿透。</li></ul></div><ul><li>流程图，如下所示：</li></ul><p><img src="`+r+`" alt="" loading="lazy"></p><h3 id="_3-5-2-应用示例" tabindex="-1">3.5.2 应用示例 <a class="header-anchor" href="#_3-5-2-应用示例" aria-label="Permalink to &quot;3.5.2 应用示例&quot;">​</a></h3><ul><li><p>需求：编写一个程序，该程序可以接收一个字符，比如：a、b、c、d；其中， a 表示星期一，b 表示星期二…，根据用户的输入显示相应的信息，要求使用 switch 语句。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> char</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> chs;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入一个字符（a、b、c、d）：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%c</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">chs);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> switch</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (chs) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;a&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;今天是星期一 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;窗前明月光 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;b&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;今天是星期二 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;疑是地上霜 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;c&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;今天是星期三 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;举头望明月 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &#39;d&#39;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;今天是星期四 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;低头思故乡 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> default</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;输入错误！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br></div></div><h3 id="_3-5-3-应用示例" tabindex="-1">3.5.3 应用示例 <a class="header-anchor" href="#_3-5-3-应用示例" aria-label="Permalink to &quot;3.5.3 应用示例&quot;">​</a></h3><ul><li><p>需求：编写程序，输入月份，输出该月份有多少天。说明：1 月、3 月、5 月、7月、8 月、10 月、12 月有 31 天，4 月、6 月、9 月、11 月有 30 天，2 月有 28 天或 29 天。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> month;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入月份 (1-12)：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">month);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> switch</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (month) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</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;"> case</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:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 5</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 7</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</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;"> case</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;"> case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 12</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 月有 31 天</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, month);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 4</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 6</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 9</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 11</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 月有 30 天</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, month);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 月有 28 天或 29 天</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, month);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> default</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;输入错误！&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br></div></div><h3 id="_3-5-4-switch-和-if-else-if-的比较" tabindex="-1">3.5.4 switch 和 if else if 的比较 <a class="header-anchor" href="#_3-5-4-switch-和-if-else-if-的比较" aria-label="Permalink to &quot;3.5.4 switch 和 if else if 的比较&quot;">​</a></h3><ul><li>① 如果判断条件是判等，而且符合整型、枚举类型，虽然两个语句都可以使用，建议使用 swtich 语句。</li><li>② 如果判断条件是区间判断，大小判断等，使用 if...else...if。</li></ul><h2 id="_3-6-嵌套分支" tabindex="-1">3.6 嵌套分支 <a class="header-anchor" href="#_3-6-嵌套分支" aria-label="Permalink to &quot;3.6 嵌套分支&quot;">​</a></h2><h3 id="_3-6-1-概述" tabindex="-1">3.6.1 概述 <a class="header-anchor" href="#_3-6-1-概述" aria-label="Permalink to &quot;3.6.1 概述&quot;">​</a></h3><ul><li>嵌套分支是指，在一个分支结构中又嵌套了另一个分支结构，里面的分支的结构称为内层分支，外面的分支结构称为外层分支。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>嵌套分支层数不宜过多，建议最多不要超过 3 层。</p></div><h3 id="_3-6-2-应用示例" tabindex="-1">3.6.2 应用示例 <a class="header-anchor" href="#_3-6-2-应用示例" aria-label="Permalink to &quot;3.6.2 应用示例&quot;">​</a></h3><ul><li>需求：根据淡旺季的月份和年龄，打印票价。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 4 -10 是旺季： <ul><li>成人（18-60）：60 。</li><li>儿童（&lt;18）：半价。</li><li>老人（&gt;60）：1/3 。</li></ul></li><li>② 其余是淡季： <ul><li>成人：40。</li><li>其他：20。</li></ul></li></ul></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> month;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> age;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> price </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 60</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入月份 (1-12)：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">month);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入年龄：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">age);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 旺季</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (month </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 4</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> &amp;&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> month </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</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;"> (age </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 18</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> price </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">/=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span 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;"> (age </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 60</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> price </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;"> }</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:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (age </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 18</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> price </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 40</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:#24292E;--shiki-dark:#E1E4E8;"> price </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:#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:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;票价: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2lf\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, price);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br></div></div><h1 id="第四章-随机数" tabindex="-1">第四章：随机数 <a class="header-anchor" href="#第四章-随机数" aria-label="Permalink to &quot;第四章：随机数&quot;">​</a></h1><h2 id="_4-1-概述" tabindex="-1">4.1 概述 <a class="header-anchor" href="#_4-1-概述" aria-label="Permalink to &quot;4.1 概述&quot;">​</a></h2><ul><li>所谓的随机数就是没有规则，并且不能预测的一些数字，也称为真随机数。</li><li>程序中也是可以产生随机数的，但是是通过一些固定规则产生的，称为伪随机数。</li><li>常见的伪随机数（线性同余方程，LCG）的公式，如下所示：</li></ul>`,84),o={class:"MathJax",jax:"SVG",style:{direction:"ltr",position:"relative"}},m={style:{overflow:"visible","min-height":"1px","min-width":"1px","vertical-align":"-0.566ex"},xmlns:"http://www.w3.org/2000/svg",width:"28.71ex",height:"2.262ex",role:"img",focusable:"false",viewBox:"0 -750 12690 1000","aria-hidden":"true"},C=i('<g stroke="currentColor" fill="currentColor" stroke-width="0" transform="scale(1,-1)"><g data-mml-node="math"><g data-mml-node="msub"><g data-mml-node="mi"><path data-c="1D44B" d="M42 0H40Q26 0 26 11Q26 15 29 27Q33 41 36 43T55 46Q141 49 190 98Q200 108 306 224T411 342Q302 620 297 625Q288 636 234 637H206Q200 643 200 645T202 664Q206 677 212 683H226Q260 681 347 681Q380 681 408 681T453 682T473 682Q490 682 490 671Q490 670 488 658Q484 643 481 640T465 637Q434 634 411 620L488 426L541 485Q646 598 646 610Q646 628 622 635Q617 635 609 637Q594 637 594 648Q594 650 596 664Q600 677 606 683H618Q619 683 643 683T697 681T738 680Q828 680 837 683H845Q852 676 852 672Q850 647 840 637H824Q790 636 763 628T722 611T698 593L687 584Q687 585 592 480L505 384Q505 383 536 304T601 142T638 56Q648 47 699 46Q734 46 734 37Q734 35 732 23Q728 7 725 4T711 1Q708 1 678 1T589 2Q528 2 496 2T461 1Q444 1 444 10Q444 11 446 25Q448 35 450 39T455 44T464 46T480 47T506 54Q523 62 523 64Q522 64 476 181L429 299Q241 95 236 84Q232 76 232 72Q232 53 261 47Q262 47 267 47T273 46Q276 46 277 46T280 45T283 42T284 35Q284 26 282 19Q279 6 276 4T261 1Q258 1 243 1T201 2T142 2Q64 2 42 0Z" style="stroke-width:3;"></path></g><g data-mml-node="TeXAtom" transform="translate(861,-150) scale(0.707)" data-mjx-texclass="ORD"><g data-mml-node="mi"><path data-c="1D45B" d="M21 287Q22 293 24 303T36 341T56 388T89 425T135 442Q171 442 195 424T225 390T231 369Q231 367 232 367L243 378Q304 442 382 442Q436 442 469 415T503 336T465 179T427 52Q427 26 444 26Q450 26 453 27Q482 32 505 65T540 145Q542 153 560 153Q580 153 580 145Q580 144 576 130Q568 101 554 73T508 17T439 -10Q392 -10 371 17T350 73Q350 92 386 193T423 345Q423 404 379 404H374Q288 404 229 303L222 291L189 157Q156 26 151 16Q138 -11 108 -11Q95 -11 87 -5T76 7T74 17Q74 30 112 180T152 343Q153 348 153 366Q153 405 129 405Q91 405 66 305Q60 285 60 284Q58 278 41 278H27Q21 284 21 287Z" style="stroke-width:3;"></path></g><g data-mml-node="mo" transform="translate(600,0)"><path data-c="2B" d="M56 237T56 250T70 270H369V420L370 570Q380 583 389 583Q402 583 409 568V270H707Q722 262 722 250T707 230H409V-68Q401 -82 391 -82H389H387Q375 -82 369 -68V230H70Q56 237 56 250Z" style="stroke-width:3;"></path></g><g data-mml-node="mn" transform="translate(1378,0)"><path data-c="31" d="M213 578L200 573Q186 568 160 563T102 556H83V602H102Q149 604 189 617T245 641T273 663Q275 666 285 666Q294 666 302 660V361L303 61Q310 54 315 52T339 48T401 46H427V0H416Q395 3 257 3Q121 3 100 0H88V46H114Q136 46 152 46T177 47T193 50T201 52T207 57T213 61V578Z" style="stroke-width:3;"></path></g></g></g><g data-mml-node="mo" transform="translate(2516.7,0)"><path data-c="3D" d="M56 347Q56 360 70 367H707Q722 359 722 347Q722 336 708 328L390 327H72Q56 332 56 347ZM56 153Q56 168 72 173H708Q722 163 722 153Q722 140 707 133H70Q56 140 56 153Z" style="stroke-width:3;"></path></g><g data-mml-node="mo" transform="translate(3572.5,0)"><path data-c="28" d="M94 250Q94 319 104 381T127 488T164 576T202 643T244 695T277 729T302 750H315H319Q333 750 333 741Q333 738 316 720T275 667T226 581T184 443T167 250T184 58T225 -81T274 -167T316 -220T333 -241Q333 -250 318 -250H315H302L274 -226Q180 -141 137 -14T94 250Z" style="stroke-width:3;"></path></g><g data-mml-node="mi" transform="translate(3961.5,0)"><path data-c="1D44E" d="M33 157Q33 258 109 349T280 441Q331 441 370 392Q386 422 416 422Q429 422 439 414T449 394Q449 381 412 234T374 68Q374 43 381 35T402 26Q411 27 422 35Q443 55 463 131Q469 151 473 152Q475 153 483 153H487Q506 153 506 144Q506 138 501 117T481 63T449 13Q436 0 417 -8Q409 -10 393 -10Q359 -10 336 5T306 36L300 51Q299 52 296 50Q294 48 292 46Q233 -10 172 -10Q117 -10 75 30T33 157ZM351 328Q351 334 346 350T323 385T277 405Q242 405 210 374T160 293Q131 214 119 129Q119 126 119 118T118 106Q118 61 136 44T179 26Q217 26 254 59T298 110Q300 114 325 217T351 328Z" style="stroke-width:3;"></path></g><g data-mml-node="mo" transform="translate(4712.7,0)"><path data-c="22C5" d="M78 250Q78 274 95 292T138 310Q162 310 180 294T199 251Q199 226 182 208T139 190T96 207T78 250Z" style="stroke-width:3;"></path></g><g data-mml-node="msub" transform="translate(5212.9,0)"><g data-mml-node="mi"><path data-c="1D44B" d="M42 0H40Q26 0 26 11Q26 15 29 27Q33 41 36 43T55 46Q141 49 190 98Q200 108 306 224T411 342Q302 620 297 625Q288 636 234 637H206Q200 643 200 645T202 664Q206 677 212 683H226Q260 681 347 681Q380 681 408 681T453 682T473 682Q490 682 490 671Q490 670 488 658Q484 643 481 640T465 637Q434 634 411 620L488 426L541 485Q646 598 646 610Q646 628 622 635Q617 635 609 637Q594 637 594 648Q594 650 596 664Q600 677 606 683H618Q619 683 643 683T697 681T738 680Q828 680 837 683H845Q852 676 852 672Q850 647 840 637H824Q790 636 763 628T722 611T698 593L687 584Q687 585 592 480L505 384Q505 383 536 304T601 142T638 56Q648 47 699 46Q734 46 734 37Q734 35 732 23Q728 7 725 4T711 1Q708 1 678 1T589 2Q528 2 496 2T461 1Q444 1 444 10Q444 11 446 25Q448 35 450 39T455 44T464 46T480 47T506 54Q523 62 523 64Q522 64 476 181L429 299Q241 95 236 84Q232 76 232 72Q232 53 261 47Q262 47 267 47T273 46Q276 46 277 46T280 45T283 42T284 35Q284 26 282 19Q279 6 276 4T261 1Q258 1 243 1T201 2T142 2Q64 2 42 0Z" style="stroke-width:3;"></path></g><g data-mml-node="mi" transform="translate(861,-150) scale(0.707)"><path data-c="1D45B" d="M21 287Q22 293 24 303T36 341T56 388T89 425T135 442Q171 442 195 424T225 390T231 369Q231 367 232 367L243 378Q304 442 382 442Q436 442 469 415T503 336T465 179T427 52Q427 26 444 26Q450 26 453 27Q482 32 505 65T540 145Q542 153 560 153Q580 153 580 145Q580 144 576 130Q568 101 554 73T508 17T439 -10Q392 -10 371 17T350 73Q350 92 386 193T423 345Q423 404 379 404H374Q288 404 229 303L222 291L189 157Q156 26 151 16Q138 -11 108 -11Q95 -11 87 -5T76 7T74 17Q74 30 112 180T152 343Q153 348 153 366Q153 405 129 405Q91 405 66 305Q60 285 60 284Q58 278 41 278H27Q21 284 21 287Z" style="stroke-width:3;"></path></g></g><g data-mml-node="mo" transform="translate(6770.4,0)"><path data-c="2B" d="M56 237T56 250T70 270H369V420L370 570Q380 583 389 583Q402 583 409 568V270H707Q722 262 722 250T707 230H409V-68Q401 -82 391 -82H389H387Q375 -82 369 -68V230H70Q56 237 56 250Z" style="stroke-width:3;"></path></g><g data-mml-node="mi" transform="translate(7770.7,0)"><path data-c="1D44F" d="M73 647Q73 657 77 670T89 683Q90 683 161 688T234 694Q246 694 246 685T212 542Q204 508 195 472T180 418L176 399Q176 396 182 402Q231 442 283 442Q345 442 383 396T422 280Q422 169 343 79T173 -11Q123 -11 82 27T40 150V159Q40 180 48 217T97 414Q147 611 147 623T109 637Q104 637 101 637H96Q86 637 83 637T76 640T73 647ZM336 325V331Q336 405 275 405Q258 405 240 397T207 376T181 352T163 330L157 322L136 236Q114 150 114 114Q114 66 138 42Q154 26 178 26Q211 26 245 58Q270 81 285 114T318 219Q336 291 336 325Z" style="stroke-width:3;"></path></g><g data-mml-node="mo" transform="translate(8199.7,0)"><path data-c="29" d="M60 749L64 750Q69 750 74 750H86L114 726Q208 641 251 514T294 250Q294 182 284 119T261 12T224 -76T186 -143T145 -194T113 -227T90 -246Q87 -249 86 -250H74Q66 -250 63 -250T58 -247T55 -238Q56 -237 66 -225Q221 -64 221 250T66 725Q56 737 55 738Q55 746 60 749Z" style="stroke-width:3;"></path></g><g data-mml-node="mspace" transform="translate(8588.7,0)"></g><g data-mml-node="mi" transform="translate(9422.3,0)"><path data-c="6D" d="M41 46H55Q94 46 102 60V68Q102 77 102 91T102 122T103 161T103 203Q103 234 103 269T102 328V351Q99 370 88 376T43 385H25V408Q25 431 27 431L37 432Q47 433 65 434T102 436Q119 437 138 438T167 441T178 442H181V402Q181 364 182 364T187 369T199 384T218 402T247 421T285 437Q305 442 336 442Q351 442 364 440T387 434T406 426T421 417T432 406T441 395T448 384T452 374T455 366L457 361L460 365Q463 369 466 373T475 384T488 397T503 410T523 422T546 432T572 439T603 442Q729 442 740 329Q741 322 741 190V104Q741 66 743 59T754 49Q775 46 803 46H819V0H811L788 1Q764 2 737 2T699 3Q596 3 587 0H579V46H595Q656 46 656 62Q657 64 657 200Q656 335 655 343Q649 371 635 385T611 402T585 404Q540 404 506 370Q479 343 472 315T464 232V168V108Q464 78 465 68T468 55T477 49Q498 46 526 46H542V0H534L510 1Q487 2 460 2T422 3Q319 3 310 0H302V46H318Q379 46 379 62Q380 64 380 200Q379 335 378 343Q372 371 358 385T334 402T308 404Q263 404 229 370Q202 343 195 315T187 232V168V108Q187 78 188 68T191 55T200 49Q221 46 249 46H265V0H257L234 1Q210 2 183 2T145 3Q42 3 33 0H25V46H41Z" style="stroke-width:3;"></path><path data-c="6F" d="M28 214Q28 309 93 378T250 448Q340 448 405 380T471 215Q471 120 407 55T250 -10Q153 -10 91 57T28 214ZM250 30Q372 30 372 193V225V250Q372 272 371 288T364 326T348 362T317 390T268 410Q263 411 252 411Q222 411 195 399Q152 377 139 338T126 246V226Q126 130 145 91Q177 30 250 30Z" transform="translate(833,0)" style="stroke-width:3;"></path><path data-c="64" d="M376 495Q376 511 376 535T377 568Q377 613 367 624T316 637H298V660Q298 683 300 683L310 684Q320 685 339 686T376 688Q393 689 413 690T443 693T454 694H457V390Q457 84 458 81Q461 61 472 55T517 46H535V0Q533 0 459 -5T380 -11H373V44L365 37Q307 -11 235 -11Q158 -11 96 50T34 215Q34 315 97 378T244 442Q319 442 376 393V495ZM373 342Q328 405 260 405Q211 405 173 369Q146 341 139 305T131 211Q131 155 138 120T173 59Q203 26 251 26Q322 26 373 103V342Z" transform="translate(1333,0)" style="stroke-width:3;"></path></g><g data-mml-node="mstyle" transform="translate(11311.3,0)"><g data-mml-node="mspace"></g></g><g data-mml-node="mstyle" transform="translate(11478.3,0)"><g data-mml-node="mspace"></g></g><g data-mml-node="mi" transform="translate(11812,0)"><path data-c="1D45A" d="M21 287Q22 293 24 303T36 341T56 388T88 425T132 442T175 435T205 417T221 395T229 376L231 369Q231 367 232 367L243 378Q303 442 384 442Q401 442 415 440T441 433T460 423T475 411T485 398T493 385T497 373T500 364T502 357L510 367Q573 442 659 442Q713 442 746 415T780 336Q780 285 742 178T704 50Q705 36 709 31T724 26Q752 26 776 56T815 138Q818 149 821 151T837 153Q857 153 857 145Q857 144 853 130Q845 101 831 73T785 17T716 -10Q669 -10 648 17T627 73Q627 92 663 193T700 345Q700 404 656 404H651Q565 404 506 303L499 291L466 157Q433 26 428 16Q415 -11 385 -11Q372 -11 364 -4T353 8T350 18Q350 29 384 161L420 307Q423 322 423 345Q423 404 379 404H374Q288 404 229 303L222 291L189 157Q156 26 151 16Q138 -11 108 -11Q95 -11 87 -5T76 7T74 17Q74 30 112 181Q151 335 151 342Q154 357 154 369Q154 405 129 405Q107 405 92 377T69 316T57 280Q55 278 41 278H27Q21 284 21 287Z" style="stroke-width:3;"></path></g></g></g>',1),B=[C],A=s("mjx-assistive-mml",{unselectable:"on",display:"inline",style:{top:"0px",left:"0px",clip:"rect(1px, 1px, 1px, 1px)","-webkit-touch-callout":"none","-webkit-user-select":"none","-khtml-user-select":"none","-moz-user-select":"none","-ms-user-select":"none","user-select":"none",position:"absolute",padding:"1px 0px 0px 0px",border:"0px",display:"block",width:"auto",overflow:"hidden"}},[s("math",{xmlns:"http://www.w3.org/1998/Math/MathML"},[s("msub",null,[s("mi",null,"X"),s("mrow",{"data-mjx-texclass":"ORD"},[s("mi",null,"n"),s("mo",null,"+"),s("mn",null,"1")])]),s("mo",null,"="),s("mo",{stretchy:"false"},"("),s("mi",null,"a"),s("mo",null,"⋅"),s("msub",null,[s("mi",null,"X"),s("mi",null,"n")]),s("mo",null,"+"),s("mi",null,"b"),s("mo",{stretchy:"false"},")"),s("mspace",{width:"0.667em"}),s("mi",null,"mod"),s("mstyle",{scriptlevel:"0"},[s("mspace",{width:"0.167em"})]),s("mstyle",{scriptlevel:"0"},[s("mspace",{width:"0.167em"})]),s("mi",null,"m")])],-1),D=i(`<ul><li>其中，X 是伪随机序列，a 是乘数（通常选择一个大于 0 的常数，典型值有 1664525），b 是增量（选择一个大于 0 的常数，典型值有 1013904223）， m 是模数（ 通常选择一个大的常数，常见值有 ( 2^{32} ) ，即 4294967296））。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>假设 a = 31 ，b = 13 ，m = 100 ；那么，伪随机数的公式就是 <code>X_{n+1} = (31 × X_n + 13) % 100 </code>。</p><ul><li>如果 <code>X_{n}</code> = 1 ，那么 <code>X_{n+1}</code> = 44 。</li><li>如果 <code>X_{n}</code> = 44 ，那么 <code>X_{n+1}</code> = 77 。</li><li>如果 <code>X_{n}</code> = 77 ，那么 <code>X_{n+1}</code> = 0 。</li><li>...</li></ul><p>最后，将得到 44、77、0、13、16、9 、92、65、28 ... ，其中 1 也称为初始种子（随机数种子）。</p></div><ul><li>工作原理： <ul><li>① 设置初始种子（X_0）： <ul><li>种子值是算法生成随机数序列的起点。</li><li>不同的种子值会产生不同的随机数序列。</li></ul></li><li>② 递归生成随机数： <ul><li>从初始种子开始，通过公式不断生成新的随机数。</li><li>每次迭代都使用前一次生成的随机数作为输入。</li></ul></li></ul></li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>如果种子的值相同，那么每次生成的随机数将相同，解决方案就是将种子的值设置为当前的时间戳。</p></div><h2 id="_4-2-c-语言中随机数的产生" tabindex="-1">4.2 C 语言中随机数的产生 <a class="header-anchor" href="#_4-2-c-语言中随机数的产生" aria-label="Permalink to &quot;4.2 C 语言中随机数的产生&quot;">​</a></h2><ul><li>① 设置随机数种子：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</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;">srand</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 style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // seed 种⼦ rand random 随机</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>随机数函数在 <code>#include &lt;stdlib.h&gt;</code> 中声明。</p></div><ul><li>② 根据随机数种⼦计算出⼀个伪随机数：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">// 根据种⼦值产⽣⼀个 0-32767 范围的随机数</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:#6F42C1;--shiki-dark:#B392F0;"> rand</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></div></div><ul><li>③ 产生一个指定范围内的随机数：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre 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:#6F42C1;--shiki-dark:#B392F0;"> random_in_range</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;"> min</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;"> max</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> rand</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;"> (max </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">-</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 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 style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> min;</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></div></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdlib.h&gt;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;time.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">// 生成指定范围的随机数的函数</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> randomInRange</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;"> min</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;"> max</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> rand</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;"> (max </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">-</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 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 style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> min;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 使用当前时间作为种子</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> srand</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">time</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">));</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 定义范围</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 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:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> max </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 生成并打印随机数</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> 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;">&lt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</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;">i) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> random </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> randomInRange</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(min, max);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, random);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br></div></div><h1 id="第五章-循环结构-⭐" tabindex="-1">第五章：循环结构（⭐） <a class="header-anchor" href="#第五章-循环结构-⭐" aria-label="Permalink to &quot;第五章：循环结构（⭐）&quot;">​</a></h1><h2 id="_5-1-概述" tabindex="-1">5.1 概述 <a class="header-anchor" href="#_5-1-概述" aria-label="Permalink to &quot;5.1 概述&quot;">​</a></h2><ul><li>循环结构：在某些条件满足的情况下，反复执行特定代码的功能。</li></ul><h2 id="_5-2-for-循环" tabindex="-1">5.2 for 循环 <a class="header-anchor" href="#_5-2-for-循环" aria-label="Permalink to &quot;5.2 for 循环&quot;">​</a></h2><h3 id="_5-2-1-概述" tabindex="-1">5.2.1 概述 <a class="header-anchor" href="#_5-2-1-概述" aria-label="Permalink to &quot;5.2.1 概述&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">for</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(初始化条件①;循环条件表达式②;迭代语句④){</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 循环体语句③</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></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 初始化条件，用于初始化循环变量，只会执行一次，且循环开始前就执行（可以声明多个变量，但是必须是同一类型，用逗号 <code>,</code> 隔开）。</li><li>② 循环条件表达式每次循环都执行，同 while 循环一样，每次先判断后执行循环体语句。</li><li>③ 迭代语句每次循环都执行，在大括号中循环体语句之后执行（如果有多个变量更新，用逗号 <code>,</code> 隔开）。</li></ul></div><ul><li>流程图，如下所示：</li></ul><p><img src="`+E+`" alt="" loading="lazy"></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>执行过程是：① --&gt; ② --&gt; ③ --&gt; ④ --&gt; ② --&gt; ③ --&gt; ④ --&gt; ... --&gt; ② 。</p></div><h3 id="_5-2-2-应用示例" tabindex="-1">5.2.2 应用示例 <a class="header-anchor" href="#_5-2-2-应用示例" aria-label="Permalink to &quot;5.2.2 应用示例&quot;">​</a></h3><ul><li><p>需求：输出 5 行 <code>Hello World!</code> 。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> 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;">; i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 5</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;">i) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;Hello World!</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<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="_5-2-3-应用示例" tabindex="-1">5.2.3 应用示例 <a class="header-anchor" href="#_5-2-3-应用示例" aria-label="Permalink to &quot;5.2.3 应用示例&quot;">​</a></h3><ul><li><p>需求：求 1 ~ 100 之内所有偶数的和，以及偶数的个数。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> sum </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;"> count </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> 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;">; i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</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;">) {</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:#005CC5;--shiki-dark:#79B8FF;"> 2</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> ==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> sum </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 style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> count</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:#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:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;1 ~ 100 中的所有偶数的和为: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, sum);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;1 ~ 100 中的所有偶数的个数为: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, count);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br></div></div><h3 id="_5-2-4-应用示例" tabindex="-1">5.2.4 应用示例 <a class="header-anchor" href="#_5-2-4-应用示例" aria-label="Permalink to &quot;5.2.4 应用示例&quot;">​</a></h3><ul><li><p>需求：输出所有的水仙花数，所谓水仙花数是指一个 3 位数，其各个位上数字立方和等于其本身，例如：<code>153 = 1×1×1 + 3×3×3 + 5×5×5</code>。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> count </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> i </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;">; i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 999</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;">) {</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 获取三位数</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;"> i </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;"> shi </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;"> 10</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;"> bai </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;"> 100</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;"> // 判定是否为水仙花数</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</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;"> ge </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">*</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;"> shi </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">*</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;"> shi </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</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;"> bai </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">*</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;"> i) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;水仙花数：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> count</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:#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:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;水仙花数总个数：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, count);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br></div></div><h3 id="_5-2-5-应用示例" tabindex="-1">5.2.5 应用示例 <a class="header-anchor" href="#_5-2-5-应用示例" aria-label="Permalink to &quot;5.2.5 应用示例&quot;">​</a></h3><ul><li><p>需求：将 1 ~ 10 倒序输出，如：10 、9 、8 ...</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> i </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;">; i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">; i</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">--</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</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></div></div><h3 id="_5-2-6-应用示例" tabindex="-1">5.2.6 应用示例 <a class="header-anchor" href="#_5-2-6-应用示例" aria-label="Permalink to &quot;5.2.6 应用示例&quot;">​</a></h3><ul><li>需求：输入两个正整数 m 和 n ，求其最大公约数和最小公倍数，例如：12 和 20 的最大公约数是 4 ，最小公倍数是 60 。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>如果数 a 能被数 b 整除，且结果是整数，那么 a 就叫做 b 的倍数，b 就叫做 a 的约数（因数）。</li><li>如果一个整数同时是几个整数的约数，则称该整数为这些整数的公约数；其中，数值最大的称为最大公约数。</li><li>如果一个整数同时为两个或多个整数的倍数的数，则称该整数为这些整数的公倍数；其中，数值最小的称为最小公倍数。</li></ul></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> m </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;">, n </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 20</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 取出两个数中的较小值</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> min </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;">&lt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n) </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">?</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> m </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">:</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> min; i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</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;">) {</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;"> (m </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;"> 0</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> &amp;&amp;</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;"> 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:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;最大公约数是：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 公约数</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> //跳出当前循环结构</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 取出两个数中的较大值</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> max </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (m </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n) </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">?</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> m </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">:</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> max; i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</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; i</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">++</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (i </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:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> &amp;&amp;</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;"> n </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;最小公倍数是：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 公倍数</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br></div></div><h2 id="_5-3-while-循环" tabindex="-1">5.3 while 循环 <a class="header-anchor" href="#_5-3-while-循环" aria-label="Permalink to &quot;5.3 while 循环&quot;">​</a></h2><h3 id="_5-3-1-概述" tabindex="-1">5.3.1 概述 <a class="header-anchor" href="#_5-3-1-概述" aria-label="Permalink to &quot;5.3.1 概述&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">初始化条件①；</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">while</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (循环条件语句②) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 循环体语句③；</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 迭代语句④；</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></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① <code>while(循环条件部分)</code> 中循环条件为<code>非0</code>值，表示 <code>true</code>、<code>真</code>；为<code>0</code>值，表示 <code>false</code>、<code>假</code>。</li><li>② 当循环条件表达式成立，就执行循环体语句，直到条件不成立停止循环。</li><li>③ 为避免死循环，循环条件表达式不能永远成立，且随着循环次数增加，应该越来越趋向于不成立。</li><li>④ for 循环和 while 循环<code>可以相互转换</code>，二者没有性能上的差别。</li><li>⑤ for 循环与 while 循环的区别：<code>初始化条件部分的作用域不同</code>。</li></ul></div><ul><li>流程图，如下所示：</li></ul><p><img src="`+d+`" alt="" loading="lazy"></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>执行过程是：① --&gt; ② --&gt; ③ --&gt; ④ --&gt; ② --&gt; ③ --&gt; ④ --&gt; ... --&gt; ② 。</p></div><h3 id="_5-3-2-应用示例" tabindex="-1">5.3.2 应用示例 <a class="header-anchor" href="#_5-3-2-应用示例" aria-label="Permalink to &quot;5.3.2 应用示例&quot;">​</a></h3><ul><li><p>需求：输出 5 行 <code>Hello World!</code> 。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"><span style="--shiki-light:#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;"> while</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 5</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;Hello World!</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> i</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:#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></div></div><h3 id="_5-3-3-应用示例" tabindex="-1">5.3.3 应用示例 <a class="header-anchor" href="#_5-3-3-应用示例" aria-label="Permalink to &quot;5.3.3 应用示例&quot;">​</a></h3><ul><li><p>需求：求 1 ~ 100 之内所有偶数的和，以及偶数的个数。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> sum </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;"> count </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> 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;"> while</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</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;"> 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:#005CC5;--shiki-dark:#79B8FF;"> 2</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> ==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> sum </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 style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> count</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:#24292E;--shiki-dark:#E1E4E8;"> }</span></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;">;</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:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;1 ~ 100 中的所有偶数的和为: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, sum);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;1 ~ 100 中的所有偶数的个数为: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, count);</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="_5-3-4-应用示例" tabindex="-1">5.3.4 应用示例 <a class="header-anchor" href="#_5-3-4-应用示例" aria-label="Permalink to &quot;5.3.4 应用示例&quot;">​</a></h3><ul><li><p>需求：世界最高山峰是珠穆朗玛峰，它的高度是 8848.86 米，假如我有一张足够大的纸，它的厚度是 0.1 毫米。请问，我折叠多少次，可以折成珠穆朗玛峰的高度?</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 折叠的次数</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> count </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 珠峰的高度</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> zfHeight </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 8848860</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;"> // 每次折叠的高度</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> paperHeight </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0.1</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;"> while</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (paperHeight </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> zfHeight) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> count</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:#24292E;--shiki-dark:#E1E4E8;"> paperHeight </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">*=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;需要折叠 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 次，才能得到珠峰的高度。</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, count);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;折纸的高度为 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2f</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 米，超过了珠峰的高度&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, paperHeight </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">/</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1000</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;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br></div></div><h3 id="_5-3-5-应用示例" tabindex="-1">5.3.5 应用示例 <a class="header-anchor" href="#_5-3-5-应用示例" aria-label="Permalink to &quot;5.3.5 应用示例&quot;">​</a></h3><ul><li>需求：给出一个整数 n ，判断该整数是否是 2 的幂次方。如果是，就输出 yes ；否则，输出 no 。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>思路：</p><ul><li>① 2^ 0 = 1 ，2^1 = 2 ，2^2 = 4，2^3 = 8，2^4 = 16，2^5 = 32 ...，规律：每一个数字都是前一个数字的 2 倍（任意一个数字，不断的除以 2 ，最终看结果是否是数字 1 ）。</li><li>② 循环终止条件： <ul><li>结果是 1 的时候，就可以结束，输出 yes 。</li><li>如果在除以 2 的时候，无法被 2 整数，也可以结束，输出 no ，如： 100 / 2 = 50，50 / 2 = 25 。</li></ul></li></ul></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 禁用 stdout 缓冲区</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> setbuf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(stdout, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">NULL</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入一个整数：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">n);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> while</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (n </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> &amp;&amp;</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;"> 2</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> ==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> n </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">/=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (n </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;yes&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;no&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br></div></div><h3 id="_5-3-6-应用示例" tabindex="-1">5.3.6 应用示例 <a class="header-anchor" href="#_5-3-6-应用示例" aria-label="Permalink to &quot;5.3.6 应用示例&quot;">​</a></h3><ul><li>需求：整数反转，如：123 --&gt; 321 。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>思路：从右边开始，依次获取每一位数字，再拼接起来。</p></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 禁用 stdout 缓冲区</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> setbuf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(stdout, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">NULL</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num </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;"> original </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;"> rev </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入一个整数：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">num);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> original </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 从右边开始，依次获取每个数字，然后拼接到 rev 中</span></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;"> * 第 1 次，123 % 10 = 3，rev = 0 * 10 + 3 = 3</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> * 第 2 次，12 % 10 = 2，rev = 3 * 10 + 2 = 32</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> * 第 3 次，1 % 10 = 1，rev = 32 * 10 + 1 = 321</span></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;"> // 循环结束的条件是 num == 0</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> while</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;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 获取 num 右边的第一位数字</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> temp </span><span style="--shiki-light:#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:#6A737D;--shiki-dark:#6A737D;"> // 去掉最后一位数字</span></span>
<span class="line"><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:#6A737D;--shiki-dark:#6A737D;"> // 将 temp 拼接到 rev 的后面</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> rev </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> rev </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:#24292E;--shiki-dark:#E1E4E8;"> temp;</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:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 的反转是 </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, original, rev);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br></div></div><h2 id="_5-4-do-while-循环" tabindex="-1">5.4 do-while 循环 <a class="header-anchor" href="#_5-4-do-while-循环" aria-label="Permalink to &quot;5.4 do-while 循环&quot;">​</a></h2><h3 id="_5-4-1-概述" tabindex="-1">5.4.1 概述 <a class="header-anchor" href="#_5-4-1-概述" aria-label="Permalink to &quot;5.4.1 概述&quot;">​</a></h3><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">①初始化部分;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">do</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">{</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ③循环体部分</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ④迭代部分</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">while</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(②循环条件部分);</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① <code>do{} while();</code>最后有一个分号。</li><li>② do-while 结构的循环体语句是至少会执行一次，这个和 for 、while 是不一样的。</li><li>③ 循环的三个结构 for、while、do-while 三者是可以相互转换的。</li></ul></div><ul><li>流程图，如下所示：</li></ul><p><img src="`+g+`" alt="" loading="lazy"></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>执行过程是：① --&gt; ③ --&gt; ④ --&gt; ② --&gt; ③ --&gt; ④ --&gt; ② --&gt; ... --&gt; ② 。</p></div><h3 id="_5-4-2-应用示例" tabindex="-1">5.4.2 应用示例 <a class="header-anchor" href="#_5-4-2-应用示例" aria-label="Permalink to &quot;5.4.2 应用示例&quot;">​</a></h3><ul><li>需求：求 1 ~ 100 之内所有偶数的和，以及偶数的个数。</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> sum </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;"> count </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> 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;"> do</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:#005CC5;--shiki-dark:#79B8FF;"> 2</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> ==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> sum </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 style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> count</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:#24292E;--shiki-dark:#E1E4E8;"> }</span></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;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">while</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;1 ~ 100 中的所有偶数的和为: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, sum);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;1 ~ 100 中的所有偶数的个数为: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, count);</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="_5-4-3-应用示例" tabindex="-1">5.4.3 应用示例 <a class="header-anchor" href="#_5-4-3-应用示例" aria-label="Permalink to &quot;5.4.3 应用示例&quot;">​</a></h3><ul><li><p>需求：实现 ATM 取款机功能。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 账户余额</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> balance </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0.0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 客户选择</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> selection;</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 存款金额</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> addMoney;</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 取款金额</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> double</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> minusMoney;</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 退出标识</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> bool</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> exitFlag </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:#D73A49;--shiki-dark:#F97583;"> do</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;=========ATM========</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\t</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">1、存款</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\t</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">2、取款</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\t</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">3、显示余额</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\t</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">4、退出</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请选择(1-4)：&quot;</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;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">selection);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> switch</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (selection) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;您当前的余额是: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2f\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, balance);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入存款金额：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lf</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">addMoney</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> balance </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> addMoney;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;存款成功，您当前的余额是：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2f\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, balance);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 2</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;您当前的余额是: </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2f\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, balance);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入取款金额：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%lf</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">minusMoney</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;"> (minusMoney </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> balance) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;余额不足，取款失败。</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> balance </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">-=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> minusMoney;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;取款成功，您的余额为：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2f\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, balance);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;您的账户余额为：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%.2f\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, balance);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> case</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 4</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> exitFlag </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> true</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;欢迎下次再来。</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> default</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">:</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;输入有误，请重新输入。</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</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:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">while</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;">exitFlag);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br><span class="line-number">38</span><br><span class="line-number">39</span><br><span class="line-number">40</span><br><span class="line-number">41</span><br><span class="line-number">42</span><br><span class="line-number">43</span><br><span class="line-number">44</span><br><span class="line-number">45</span><br><span class="line-number">46</span><br><span class="line-number">47</span><br><span class="line-number">48</span><br><span class="line-number">49</span><br><span class="line-number">50</span><br><span class="line-number">51</span><br><span class="line-number">52</span><br><span class="line-number">53</span><br><span class="line-number">54</span><br><span class="line-number">55</span><br><span class="line-number">56</span><br><span class="line-number">57</span><br><span class="line-number">58</span><br></div></div><h2 id="_5-5-嵌套循环" tabindex="-1">5.5 嵌套循环 <a class="header-anchor" href="#_5-5-嵌套循环" aria-label="Permalink to &quot;5.5 嵌套循环&quot;">​</a></h2><h3 id="_5-5-1-概述" tabindex="-1">5.5.1 概述 <a class="header-anchor" href="#_5-5-1-概述" aria-label="Permalink to &quot;5.5.1 概述&quot;">​</a></h3><ul><li>所谓的嵌套循环，是指一个循环结构 A 的循环体是另一个循环结构 B 。例如：for 循环里面还有一个for 循环，就是嵌套循环。</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:#D73A49;--shiki-dark:#F97583;">for</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(初始化语句①; 循环条件语句②; 迭代语句⑦) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(初始化语句③; 循环条件语句④; 迭代语句⑥) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> 循环体语句⑤;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br></div></div><ul><li>其中，for 、while 、do-while 均可以作为外层循环或内层循环。 <ul><li>外层循环：循环结构 A</li><li>内层循环：循环结构 B</li></ul></li></ul><p><img src="`+c+`" alt="" loading="lazy"></p><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 实际上，嵌套循环就是将内层循环当成外层循环的循环体。当只有内层循环的循环条件为 false ，才会完全跳出内层循环，才可结束外层的当次循环，开始下一次循环。</li><li>② 假设外层循环次数为 m 次，内层循环次数为 n 次，则内层循环体实际上需要执行 m × n 次。</li><li>③ 从二维图形的角度看，外层循环控制<code>行数</code>，内层循环控制<code>列数</code>。</li><li>④ 实际开发中，我们最多见到的嵌套循环是两层，一般不会出现超过三层的嵌套循环。如果将要出现，一定要停下来重新梳理业务逻辑，重新思考算法的实现，控制在三层以内；否则，可读性会很差。</li></ul></div><h3 id="_5-5-2-应用示例" tabindex="-1">5.5.2 应用示例 <a class="header-anchor" href="#_5-5-2-应用示例" aria-label="Permalink to &quot;5.5.2 应用示例&quot;">​</a></h3><ul><li><p>需求：打印 5 行 <code>*</code> ，要求每行 6 个 <code>*</code> 。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> 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;">; i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 5</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;">i) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> j </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;">&lt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 6</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;">j) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;* &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<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><h3 id="_5-5-3-应用示例" tabindex="-1">5.5.3 应用示例 <a class="header-anchor" href="#_5-5-3-应用示例" aria-label="Permalink to &quot;5.5.3 应用示例&quot;">​</a></h3><ul><li><p>需求：打印 5 行直角三角形。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> 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;">; i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 5</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;">i) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> j </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;">&lt;=</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>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;* &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<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><h3 id="_5-5-4-应用示例" tabindex="-1">5.5.4 应用示例 <a class="header-anchor" href="#_5-5-4-应用示例" aria-label="Permalink to &quot;5.5.4 应用示例&quot;">​</a></h3><ul><li><p>需求：打印 5 行倒直角三角形。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> 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;">; i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 5</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;">i) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> j </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;">&lt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 6</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:#24292E;--shiki-dark:#E1E4E8;">j) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;* &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<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><h3 id="_5-5-5-应用示例" tabindex="-1">5.5.5 应用示例 <a class="header-anchor" href="#_5-5-5-应用示例" aria-label="Permalink to &quot;5.5.5 应用示例&quot;">​</a></h3><ul><li><p>需求：打印 9 <code>×</code> 9 乘法表。</p></li><li><p>示例：</p></li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> 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;">; i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 9</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;">i) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> j </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;">&lt;=</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>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> × </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> = </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i, j, i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">*</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> j);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br></div></div><h2 id="_5-6-无限循环" tabindex="-1">5.6 无限循环 <a class="header-anchor" href="#_5-6-无限循环" aria-label="Permalink to &quot;5.6 无限循环&quot;">​</a></h2><ul><li>语法：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">while</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">){</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ...</span></span>
<span class="line"><span 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></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;">for</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(;;){</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> ...</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br></div></div><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><ul><li>① 在开发中，有的时候并不确定需要循环多少次，就需要根据循环体内部的某些条件，来控制循环的结束（break）。</li><li>② 如果上述的循环结构不能终止，就会构成死循环；所以，在实际开发中，要避免出现死循环！！！</li></ul></div><ul><li>示例：从键盘读入个数不确定的整数，并判断读入的正数和负数的个数，输入为 0 时结束程序</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 记录输入的整数</span></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;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 记录正数个数</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> positiveCount </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:#6A737D;--shiki-dark:#6A737D;"> // 记录负数个数</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> int</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> negativeCount </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> while</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">true</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入一个整数：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">num);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&gt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> positiveCount</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:#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;"> (num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;</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;"> negativeCount</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:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;程序结束！</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;正数的个数：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, positiveCount);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;负数的个数：</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, negativeCount);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br></div></div><h2 id="_5-7-跳转控制语句" tabindex="-1">5.7 跳转控制语句 <a class="header-anchor" href="#_5-7-跳转控制语句" aria-label="Permalink to &quot;5.7 跳转控制语句&quot;">​</a></h2><h3 id="_5-7-1-break" tabindex="-1">5.7.1 break <a class="header-anchor" href="#_5-7-1-break" aria-label="Permalink to &quot;5.7.1 break&quot;">​</a></h3><ul><li>break 的使用场景：break 语句用于终止某个语句块的执行，用在switch语句或者循环语句中。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>break 一旦执行，就结束(或跳出)当前循环结构；并且，此关键字的后面，不能声明其它语句。</p></div><ul><li>流程图，如下所示：</li></ul><p><img src="`+y+`" alt="" loading="lazy"></p><ul><li>示例：打印 0 ~ 10 ，如果遇到 <code>3</code> ，就停止打印</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> 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;">&lt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</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;">i) {</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:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</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:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;程序结束！</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"></span>
<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：编写程序，要求输入一个数字，判断该数字是否是质数</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> bool</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> isFlag </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:#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;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> do</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;请输入一个整数（必须大于 1 ）：&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> scanf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&amp;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">num);</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;"> (num </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 1</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;输入的数字不是合法，请重新输入！！！</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> isFlag </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> true</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> isFlag </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> false</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">while</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (isFlag);</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;"> isPrime </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> true</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> i </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;">; i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> num; i</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">++</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</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;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> isPrime </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:#D73A49;--shiki-dark:#F97583;"> break</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (isPrime) {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 是一个质数</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> } </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">else</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> 不是一个质数</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, num);</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:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;程序结束！</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 0</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br></div></div><h3 id="_5-7-2-continue" tabindex="-1">5.7.2 continue <a class="header-anchor" href="#_5-7-2-continue" aria-label="Permalink to &quot;5.7.2 continue&quot;">​</a></h3><ul><li>continue 的使用场景：continue 语句用于结束本次循环，继续执行下一次循环。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>continue 一旦执行，就结束(或跳出)当次循环结构；并且，此关键字的后面，不能声明其它语句。</p></div><ul><li>流程图，如下所示：</li></ul><p><img src="`+F+`" alt="" loading="lazy"></p><ul><li>示例：打印 0 ~ 10 ，如果遇到 <code>3</code> ，就继续下一次打印</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> 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;">&lt;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 10</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;">i) {</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:#005CC5;--shiki-dark:#79B8FF;"> 3</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> continue</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> \\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</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:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;程序结束！</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"></span>
<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：输出 100 以内（包括 100）的数字，跳过那些 7 的倍数或包含 7 的数字</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> 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;">; i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</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;">) {</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:#005CC5;--shiki-dark:#79B8FF;"> 7</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:#24292E;--shiki-dark:#E1E4E8;"> i </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;"> 7</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;"> 10</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> ==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 7</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> continue</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">;</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</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:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;程序结束！</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"></span>
<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><h3 id="_5-7-3-return" tabindex="-1">5.7.3 return <a class="header-anchor" href="#_5-7-3-return" aria-label="Permalink to &quot;5.7.3 return&quot;">​</a></h3><ul><li>return ：并非专门用于结束循环的，它的功能是结束一个方法。当一个方法执行到一个 return 语句的时候，这个方法将被结束。</li></ul><div class="note custom-block github-alert"><p class="custom-block-title">NOTE</p><p></p><p>和 break 和 continue 不同的是，return 直接结束整个方法，不管这个 return 处于多少层循环之内。</p></div><ul><li>示例：</li></ul><div class="language-c vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">c</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">#include</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &lt;stdio.h&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> for</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;"> 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;">; i </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">&lt;=</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 100</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;">) {</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:#005CC5;--shiki-dark:#79B8FF;"> 7</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:#24292E;--shiki-dark:#E1E4E8;"> i </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;"> 7</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;"> 10</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> ==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> 7</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span 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 style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // 结束整个函数或方法</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> }</span></span>
<span class="line"><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">%d</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, i);</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:#6F42C1;--shiki-dark:#B392F0;"> printf</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;程序结束！</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\\n</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"></span>
<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>`,133);function v(q,f,Q,T,_,x){return n(),a("div",null,[u,s("p",null,[s("mjx-container",o,[(n(),a("svg",m,B)),A])]),D])}const P=l(b,[["render",v]]);export{H as __pageData,P as default};
Reference in New Issue View Git Blame Copy Permalink