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class="tags" href="/C.html" title=c >c ap="round" d="M5,0 0,2.5 5,5z" id="raphael-marker-bloc lass="tags" href="/C.html" title=c >c k" style="-webkit-tap-highlight-c lass="tags" href="/C.html" title=c >c olor: rgba(0, 0, 0, 0);"> c >c ="https://i-blog.c lass="tags" href="/C.html" title=c >c sdnimg.c lass="tags" href="/C.html" title=c >c n/direc lass="tags" href="/C.html" title=c >c t/c lass="tags" href="/C.html" title=c >c b7f73c lass="tags" href="/C.html" title=c >c da1a14130840e356c lass="tags" href="/C.html" title=c >c b0b6f9e4.png#pic lass="tags" href="/C.html" title=c >c _c lass="tags" href="/C.html" title=c >c enter" alt="在这里插入图片描述" width="100" />
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c >
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博客主页： [小ᶻ☡꙳ᵃⁱᵍᶜ꙳]
class="tags" href="/C.html" title=
c >
c enter>
<
c lass="tags" href="/C.html" title=
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本文专栏: C++
class="tags" href="/C.html" title=
c >
c enter>
c >c ="https://img-blog.c lass="tags" href="/C.html" title=c >c sdnimg.c lass="tags" href="/C.html" title=c >c n/direc lass="tags" href="/C.html" title=c >c t/00d4fdeb7b0d4dbb99e88f325ef249d8.gif#pic lass="tags" href="/C.html" title=c >c _c lass="tags" href="/C.html" title=c >c enter" alt="在这里插入图片描述" width="1000" height="100" />
C++计算机软件开发中c lass="tags" href="/C.html" title=c >c ;对字符串进行操作是常见的需求。字符串里的查询功能是基础c lass="tags" href="/C.html" title=c >c ;也是高性能编程中的重要一环。C++ 中提供了完善的字符串操作函数c lass="tags" href="/C.html" title=c >c ;而其中的 <c lass="tags" href="/C.html" title=c >c ode>find()class="tags" href="/C.html" title=c >c ode> 函数c lass="tags" href="/C.html" title=c >c ;是用于在字符串中查找子串或字符的工具。c lass="tags" href="/C.html" title=c >c ode>find()class="tags" href="/C.html" title=c >c ode> 函数c lass="tags" href="/C.html" title=c >c ;包括基础解释c lass="tags" href="/C.html" title=c >c ;示例解析c lass="tags" href="/C.html" title=c >c ;以及实际应用中的特别经验。我们将重点解析不同功能开发情景中的实现c lass="tags" href="/C.html" title=c >c ;并提供简单明显的实验代码。c >c ="https://i-blog.c lass="tags" href="/C.html" title=c >c sdnimg.c lass="tags" href="/C.html" title=c >c n/direc lass="tags" href="/C.html" title=c >c t/f0db7c lass="tags" href="/C.html" title=c >c 348331440fa266b3c lass="tags" href="/C.html" title=c >c 24f558694.png#pic lass="tags" href="/C.html" title=c >c _c lass="tags" href="/C.html" title=c >c enter" alt="在这里插入图片描述" /> c lass="tags" href="/C.html" title=c >c ode>find()class="tags" href="/C.html" title=c >c ode> 函数概述C++ 中的 <c lass="tags" href="/C.html" title=c >c ode>find()class="tags" href="/C.html" title=c >c ode> 函数是用于在字符串中查找指定的子串或单个字符c lass="tags" href="/C.html" title=c >c ;并返回子串/字符在字符串中的第一次出现位置。
如果查找成功c lass="tags" href="/C.html" title=c >c ;则返回子串位置的值（起始位置）； 如果查找失败c lass="tags" href="/C.html" title=c >c ;则返回特殊值 <c lass="tags" href="/C.html" title=c >c ode>string::nposclass="tags" href="/C.html" title=c >c ode>c lass="tags" href="/C.html" title=c >c ;表示没有找到。 <c lass="tags" href="/C.html" title=c >c ode>find()class="tags" href="/C.html" title=c >c ode> 是字符串类的成员函数c lass="tags" href="/C.html" title=c >c ;提供了多种不同调用模式：
<c lass="tags" href="/C.html" title=c >c ode c lass="tags" href="/C.html" title=c >c lass="prism language-c lass="tags" href="/C.html" title=c >c pp">size_t class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">find class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token keyword">c lass="tags" href="/C.html" title=c >c onst stringclass="tags" href="/C.html" title=c >c lass="token operator">& strclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">, size_t pos class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token number">0 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token keyword">c lass="tags" href="/C.html" title=c >c onst class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// 查找字符串
size_t class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">find class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token keyword">c lass="tags" href="/C.html" title=c >c onst class="tags" href="/C.html" title=c >c lass="token keyword">c lass="tags" href="/C.html" title=c >c har class="tags" href="/C.html" title=c >c lass="token operator">* sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">, size_t pos class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token number">0 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token keyword">c lass="tags" href="/C.html" title=c >c onst class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// 查找 C 风格字符串
size_t class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">find class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token keyword">c lass="tags" href="/C.html" title=c >c onst class="tags" href="/C.html" title=c >c lass="token keyword">c lass="tags" href="/C.html" title=c >c har class="tags" href="/C.html" title=c >c lass="token operator">* sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">, size_t posclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">, size_t nclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token keyword">c lass="tags" href="/C.html" title=c >c onst class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// 查找指定长度子串
size_t class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">find class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token keyword">c lass="tags" href="/C.html" title=c >c har c lass="tags" href="/C.html" title=c >c class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">, size_t pos class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token number">0 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token keyword">c lass="tags" href="/C.html" title=c >c onst class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// 查找单个字符
class="tags" href="/C.html" title=c >c ode>
<c lass="tags" href="/C.html" title=c >c ode>strclass="tags" href="/C.html" title=c >c ode> ：指定的查找子串； <c lass="tags" href="/C.html" title=c >c ode>sclass="tags" href="/C.html" title=c >c ode> ： C 风格字符串c lass="tags" href="/C.html" title=c >c ;通过指针传递； <c lass="tags" href="/C.html" title=c >c ode>posclass="tags" href="/C.html" title=c >c ode> ：开始查找的位置c lass="tags" href="/C.html" title=c >c ;默认为 0； <c lass="tags" href="/C.html" title=c >c ode>nclass="tags" href="/C.html" title=c >c ode> ：要匹配的子串长度； <c lass="tags" href="/C.html" title=c >c ode>c lass="tags" href="/C.html" title=c >c class="tags" href="/C.html" title=c >c ode> ：单个字符。 如果在字符串中没有找到子串c lass="tags" href="/C.html" title=c >c ;<c lass="tags" href="/C.html" title=c >c ode>find()class="tags" href="/C.html" title=c >c ode> 函数将返回字符串类的静态常量 <c lass="tags" href="/C.html" title=c >c ode>nposclass="tags" href="/C.html" title=c >c ode> c lass="tags" href="/C.html" title=c >c ;表示失败。
<c lass="tags" href="/C.html" title=c >c ode>nposclass="tags" href="/C.html" title=c >c ode> 是字符串类中定义的静态常量c lass="tags" href="/C.html" title=c >c ;应用于不实效的查找情况：
<c lass="tags" href="/C.html" title=c >c ode c lass="tags" href="/C.html" title=c >c lass="prism language-c lass="tags" href="/C.html" title=c >c pp">class="tags" href="/C.html" title=c >c lass="token keyword">static lass="tags" href="/C.html" title=c >c class="tags" href="/C.html" title=c >c lass="token keyword">c lass="tags" href="/C.html" title=c >c onst size_t npos class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token operator">- class="tags" href="/C.html" title=c >c lass="token number">1 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// npos通常是一个特殊大的值c lass="tags" href="/C.html" title=c >c ;如：18446744073709551615
class="tags" href="/C.html" title=c >c ode>
实例：
<c lass="tags" href="/C.html" title=c >c ode c lass="tags" href="/C.html" title=c >c lass="prism language-c lass="tags" href="/C.html" title=c >c pp">class="tags" href="/C.html" title=c >c lass="token mac lass="tags" href="/C.html" title=c >c ro property">class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive-hash"># class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive keyword">inc lass="tags" href="/C.html" title=c >c lude class="tags" href="/C.html" title=c >c lass="token string"><iostream>
class="tags" href="/C.html" title=c >c lass="token mac lass="tags" href="/C.html" title=c >c ro property">class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive-hash"># class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive keyword">inc lass="tags" href="/C.html" title=c >c lude class="tags" href="/C.html" title=c >c lass="token string"><string>
class="tags" href="/C.html" title=c >c lass="token keyword">using class="tags" href="/C.html" title=c >c lass="token keyword">namespac lass="tags" href="/C.html" title=c >c e stdclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token keyword">int class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">main class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">{ string s class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token string">"hello world" class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; size_t n class="tags" href="/C.html" title=c >c lass="token operator">= sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">find class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token string">"bit" class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// "bit" 不存在c lass="tags" href="/C.html" title=c >c ;回调 npos class="tags" href="/C.html" title=c >c lass="token keyword">if class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( n class="tags" href="/C.html" title=c >c lass="token operator">== stringclass="tags" href="/C.html" title=c >c lass="token double-c lass="tags" href="/C.html" title=c >c olon punc lass="tags" href="/C.html" title=c >c tuation">:: nposclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">{ c lass="tags" href="/C.html" title=c >c out class="tags" href="/C.html" title=c >c lass="token operator"><< class="tags" href="/C.html" title=c >c lass="token string">"查找失败" class="tags" href="/C.html" title=c >c lass="token operator"><< endlclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">} class="tags" href="/C.html" title=c >c lass="token keyword">else class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">{ c lass="tags" href="/C.html" title=c >c out class="tags" href="/C.html" title=c >c lass="token operator"><< class="tags" href="/C.html" title=c >c lass="token string">"找到c lass="tags" href="/C.html" title=c >c ;位置是：" class="tags" href="/C.html" title=c >c lass="token operator"><< n class="tags" href="/C.html" title=c >c lass="token operator"><< endlclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">} class="tags" href="/C.html" title=c >c lass="token keyword">return class="tags" href="/C.html" title=c >c lass="token number">0 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">;
class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">}
class="tags" href="/C.html" title=c >c ode>
输出： c lass="tags" href="/C.html" title=c >c ode>查找失败class="tags" href="/C.html" title=c >c ode>
本例用于查找字符串中指定子串的位置：
<c lass="tags" href="/C.html" title=c >c ode c lass="tags" href="/C.html" title=c >c lass="prism language-c lass="tags" href="/C.html" title=c >c pp">class="tags" href="/C.html" title=c >c lass="token mac lass="tags" href="/C.html" title=c >c ro property">class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive-hash"># class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive keyword">inc lass="tags" href="/C.html" title=c >c lude class="tags" href="/C.html" title=c >c lass="token string"><iostream>
class="tags" href="/C.html" title=c >c lass="token mac lass="tags" href="/C.html" title=c >c ro property">class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive-hash"># class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive keyword">inc lass="tags" href="/C.html" title=c >c lude class="tags" href="/C.html" title=c >c lass="token string"><string>
class="tags" href="/C.html" title=c >c lass="token keyword">using class="tags" href="/C.html" title=c >c lass="token keyword">namespac lass="tags" href="/C.html" title=c >c e stdclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token keyword">int class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">main class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">{ string s class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token string">"hello world hello everyone" class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; string str class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token string">"llo" class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; size_t n class="tags" href="/C.html" title=c >c lass="token operator">= sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">find class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( strclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// 查找字符串 "llo"c lass="tags" href="/C.html" title=c >c ;从字符串开始 c lass="tags" href="/C.html" title=c >c out class="tags" href="/C.html" title=c >c lass="token operator"><< n class="tags" href="/C.html" title=c >c lass="token operator"><< endlclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// 输出：2 n class="tags" href="/C.html" title=c >c lass="token operator">= sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">find class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( strclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">, n class="tags" href="/C.html" title=c >c lass="token operator">+ class="tags" href="/C.html" title=c >c lass="token number">1 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// 从上次位置之后再查找 c lass="tags" href="/C.html" title=c >c out class="tags" href="/C.html" title=c >c lass="token operator"><< n class="tags" href="/C.html" title=c >c lass="token operator"><< endlclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// 输出：14 class="tags" href="/C.html" title=c >c lass="token keyword">return class="tags" href="/C.html" title=c >c lass="token number">0 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">;
class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">}
class="tags" href="/C.html" title=c >c ode>
解释：
<c lass="tags" href="/C.html" title=c >c ode>find()class="tags" href="/C.html" title=c >c ode> 实现了查找子串的功能c lass="tags" href="/C.html" title=c >c ;并且返回第一次匹配的位置。 完成一次查找后c lass="tags" href="/C.html" title=c >c ;通过 <c lass="tags" href="/C.html" title=c >c ode>n + 1class="tags" href="/C.html" title=c >c ode> 跳过已查找部分c lass="tags" href="/C.html" title=c >c ;继续找到下一个第一匹配。 如果查找单个字符c lass="tags" href="/C.html" title=c >c ;可使用下列代码：
<c lass="tags" href="/C.html" title=c >c ode c lass="tags" href="/C.html" title=c >c lass="prism language-c lass="tags" href="/C.html" title=c >c pp">class="tags" href="/C.html" title=c >c lass="token mac lass="tags" href="/C.html" title=c >c ro property">class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive-hash"># class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive keyword">inc lass="tags" href="/C.html" title=c >c lude class="tags" href="/C.html" title=c >c lass="token string"><iostream>
class="tags" href="/C.html" title=c >c lass="token mac lass="tags" href="/C.html" title=c >c ro property">class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive-hash"># class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive keyword">inc lass="tags" href="/C.html" title=c >c lude class="tags" href="/C.html" title=c >c lass="token string"><string>
class="tags" href="/C.html" title=c >c lass="token keyword">using class="tags" href="/C.html" title=c >c lass="token keyword">namespac lass="tags" href="/C.html" title=c >c e stdclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token keyword">int class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">main class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">{ string s class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token string">"hello world hello everyone" class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; size_t n class="tags" href="/C.html" title=c >c lass="token operator">= sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">find class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c har">'o' class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// 查找字符 'o'c lass="tags" href="/C.html" title=c >c ;从字符串开始 c lass="tags" href="/C.html" title=c >c out class="tags" href="/C.html" title=c >c lass="token operator"><< n class="tags" href="/C.html" title=c >c lass="token operator"><< endlclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// 输出：4 n class="tags" href="/C.html" title=c >c lass="token operator">= sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">find class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c har">'o' class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">, n class="tags" href="/C.html" title=c >c lass="token operator">+ class="tags" href="/C.html" title=c >c lass="token number">1 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// 从上次位置之后再查找 c lass="tags" href="/C.html" title=c >c out class="tags" href="/C.html" title=c >c lass="token operator"><< n class="tags" href="/C.html" title=c >c lass="token operator"><< endlclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// 输出：7 class="tags" href="/C.html" title=c >c lass="token keyword">return class="tags" href="/C.html" title=c >c lass="token number">0 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">;
class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">}
class="tags" href="/C.html" title=c >c ode>
解释：
与字符串查找相比c lass="tags" href="/C.html" title=c >c ;单字符查找更简单c lass="tags" href="/C.html" title=c >c ;参数是一个字符。 <c lass="tags" href="/C.html" title=c >c ode>find()class="tags" href="/C.html" title=c >c ode> 会返回字符在字符串中第一次出现的位置c lass="tags" href="/C.html" title=c >c ;如果找到了多次c lass="tags" href="/C.html" title=c >c ;可以通过连续查找进一步获取后续结果。 通过判断返回值是否为 <c lass="tags" href="/C.html" title=c >c ode>nposclass="tags" href="/C.html" title=c >c ode>c lass="tags" href="/C.html" title=c >c ;可以确实子串是否存在：
<c lass="tags" href="/C.html" title=c >c ode c lass="tags" href="/C.html" title=c >c lass="prism language-c lass="tags" href="/C.html" title=c >c pp">class="tags" href="/C.html" title=c >c lass="token mac lass="tags" href="/C.html" title=c >c ro property">class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive-hash"># class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive keyword">inc lass="tags" href="/C.html" title=c >c lude class="tags" href="/C.html" title=c >c lass="token string"><iostream>
class="tags" href="/C.html" title=c >c lass="token mac lass="tags" href="/C.html" title=c >c ro property">class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive-hash"># class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive keyword">inc lass="tags" href="/C.html" title=c >c lude class="tags" href="/C.html" title=c >c lass="token string"><string>
class="tags" href="/C.html" title=c >c lass="token keyword">using class="tags" href="/C.html" title=c >c lass="token keyword">namespac lass="tags" href="/C.html" title=c >c e stdclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token keyword">int class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">main class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">{ string s class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token string">"hello world hello everyone" class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; string str class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token string">"bit" class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; size_t n class="tags" href="/C.html" title=c >c lass="token operator">= sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">find class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( strclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token keyword">if class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( n class="tags" href="/C.html" title=c >c lass="token operator">!= stringclass="tags" href="/C.html" title=c >c lass="token double-c lass="tags" href="/C.html" title=c >c olon punc lass="tags" href="/C.html" title=c >c tuation">:: nposclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">{ c lass="tags" href="/C.html" title=c >c out class="tags" href="/C.html" title=c >c lass="token operator"><< class="tags" href="/C.html" title=c >c lass="token string">"找到c lass="tags" href="/C.html" title=c >c ;位置是：" class="tags" href="/C.html" title=c >c lass="token operator"><< n class="tags" href="/C.html" title=c >c lass="token operator"><< endlclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">} class="tags" href="/C.html" title=c >c lass="token keyword">else class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">{ c lass="tags" href="/C.html" title=c >c out class="tags" href="/C.html" title=c >c lass="token operator"><< class="tags" href="/C.html" title=c >c lass="token string">"没有找到" class="tags" href="/C.html" title=c >c lass="token operator"><< endlclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">} class="tags" href="/C.html" title=c >c lass="token keyword">return class="tags" href="/C.html" title=c >c lass="token number">0 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">;
class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">}
class="tags" href="/C.html" title=c >c ode>
解释：
<c lass="tags" href="/C.html" title=c >c ode>nposclass="tags" href="/C.html" title=c >c ode> 是一个特殊值c lass="tags" href="/C.html" title=c >c ;代表未找到子串。 可以通过判断 <c lass="tags" href="/C.html" title=c >c ode>n == string::nposclass="tags" href="/C.html" title=c >c ode> 确定查找是否成功c lass="tags" href="/C.html" title=c >c ;并做对应处理。 一些应用场景需要迭代找出所有匹配位置：
<c lass="tags" href="/C.html" title=c >c ode c lass="tags" href="/C.html" title=c >c lass="prism language-c lass="tags" href="/C.html" title=c >c pp">class="tags" href="/C.html" title=c >c lass="token mac lass="tags" href="/C.html" title=c >c ro property">class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive-hash"># class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive keyword">inc lass="tags" href="/C.html" title=c >c lude class="tags" href="/C.html" title=c >c lass="token string"><iostream>
class="tags" href="/C.html" title=c >c lass="token mac lass="tags" href="/C.html" title=c >c ro property">class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive-hash"># class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive keyword">inc lass="tags" href="/C.html" title=c >c lude class="tags" href="/C.html" title=c >c lass="token string"><string>
class="tags" href="/C.html" title=c >c lass="token keyword">using class="tags" href="/C.html" title=c >c lass="token keyword">namespac lass="tags" href="/C.html" title=c >c e stdclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token keyword">int class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">main class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">{ string s class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token string">"hello world hello everyone" class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; string str class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token string">"llo" class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; size_t pos class="tags" href="/C.html" title=c >c lass="token operator">= sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">find class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( strclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token keyword">while class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( pos class="tags" href="/C.html" title=c >c lass="token operator">!= stringclass="tags" href="/C.html" title=c >c lass="token double-c lass="tags" href="/C.html" title=c >c olon punc lass="tags" href="/C.html" title=c >c tuation">:: nposclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">{ c lass="tags" href="/C.html" title=c >c out class="tags" href="/C.html" title=c >c lass="token operator"><< class="tags" href="/C.html" title=c >c lass="token string">"找到：" class="tags" href="/C.html" title=c >c lass="token operator"><< pos class="tags" href="/C.html" title=c >c lass="token operator"><< endlclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; pos class="tags" href="/C.html" title=c >c lass="token operator">= sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">find class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( strclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">, pos class="tags" href="/C.html" title=c >c lass="token operator">+ class="tags" href="/C.html" title=c >c lass="token number">1 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// 继续查找 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">} class="tags" href="/C.html" title=c >c lass="token keyword">return class="tags" href="/C.html" title=c >c lass="token number">0 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">;
class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">}
class="tags" href="/C.html" title=c >c ode>
输出：
<c lass="tags" href="/C.html" title=c >c ode>找到：2
找到：14
class="tags" href="/C.html" title=c >c ode>
<c lass="tags" href="/C.html" title=c >c ode>find()class="tags" href="/C.html" title=c >c ode> 函数还可以结合 <c lass="tags" href="/C.html" title=c >c ode>substr()class="tags" href="/C.html" title=c >c ode> 提取匹配子串周围的上下文：
<c lass="tags" href="/C.html" title=c >c ode c lass="tags" href="/C.html" title=c >c lass="prism language-c lass="tags" href="/C.html" title=c >c pp">class="tags" href="/C.html" title=c >c lass="token mac lass="tags" href="/C.html" title=c >c ro property">class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive-hash"># class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive keyword">inc lass="tags" href="/C.html" title=c >c lude class="tags" href="/C.html" title=c >c lass="token string"><iostream>
class="tags" href="/C.html" title=c >c lass="token mac lass="tags" href="/C.html" title=c >c ro property">class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive-hash"># class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive keyword">inc lass="tags" href="/C.html" title=c >c lude class="tags" href="/C.html" title=c >c lass="token string"><string>
class="tags" href="/C.html" title=c >c lass="token keyword">using class="tags" href="/C.html" title=c >c lass="token keyword">namespac lass="tags" href="/C.html" title=c >c e stdclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token keyword">int class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">main class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">{ string s class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token string">"hello world hello everyone" class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; string str class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token string">"world" class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; size_t pos class="tags" href="/C.html" title=c >c lass="token operator">= sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">find class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( strclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token keyword">if class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( pos class="tags" href="/C.html" title=c >c lass="token operator">!= stringclass="tags" href="/C.html" title=c >c lass="token double-c lass="tags" href="/C.html" title=c >c olon punc lass="tags" href="/C.html" title=c >c tuation">:: nposclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">{ size_t start class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( pos class="tags" href="/C.html" title=c >c lass="token operator">> class="tags" href="/C.html" title=c >c lass="token number">5 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token operator">? pos class="tags" href="/C.html" title=c >c lass="token operator">- class="tags" href="/C.html" title=c >c lass="token number">5 class="tags" href="/C.html" title=c >c lass="token operator">: class="tags" href="/C.html" title=c >c lass="token number">0 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; size_t len class="tags" href="/C.html" title=c >c lass="token operator">= strclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">length class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token operator">+ class="tags" href="/C.html" title=c >c lass="token number">10 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; c lass="tags" href="/C.html" title=c >c out class="tags" href="/C.html" title=c >c lass="token operator"><< class="tags" href="/C.html" title=c >c lass="token string">"上下文：" class="tags" href="/C.html" title=c >c lass="token operator"><< sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">substr class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( startclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">, lenclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token operator"><< endlclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">} class="tags" href="/C.html" title=c >c lass="token keyword">return class="tags" href="/C.html" title=c >c lass="token number">0 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">;
class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">}
class="tags" href="/C.html" title=c >c ode>
输出：
<c lass="tags" href="/C.html" title=c >c ode>上下文：hello world hello
class="tags" href="/C.html" title=c >c ode>
<c lass="tags" href="/C.html" title=c >c ode>find()class="tags" href="/C.html" title=c >c ode> 函数默认区分大小写。如果需要忽略大小写c lass="tags" href="/C.html" title=c >c ;可以先将字符串转换为小写后再查找：
<c lass="tags" href="/C.html" title=c >c ode c lass="tags" href="/C.html" title=c >c lass="prism language-c lass="tags" href="/C.html" title=c >c pp">class="tags" href="/C.html" title=c >c lass="token mac lass="tags" href="/C.html" title=c >c ro property">class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive-hash"># class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive keyword">inc lass="tags" href="/C.html" title=c >c lude class="tags" href="/C.html" title=c >c lass="token string"><iostream>
class="tags" href="/C.html" title=c >c lass="token mac lass="tags" href="/C.html" title=c >c ro property">class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive-hash"># class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive keyword">inc lass="tags" href="/C.html" title=c >c lude class="tags" href="/C.html" title=c >c lass="token string"><string>
class="tags" href="/C.html" title=c >c lass="token mac lass="tags" href="/C.html" title=c >c ro property">class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive-hash"># class="tags" href="/C.html" title=c >c lass="token direc lass="tags" href="/C.html" title=c >c tive keyword">inc lass="tags" href="/C.html" title=c >c lude class="tags" href="/C.html" title=c >c lass="token string"><algorithm>
class="tags" href="/C.html" title=c >c lass="token keyword">using class="tags" href="/C.html" title=c >c lass="token keyword">namespac lass="tags" href="/C.html" title=c >c e stdclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token keyword">int class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">main class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">{ string s class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token string">"Hello World Hello Everyone" class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; string str class="tags" href="/C.html" title=c >c lass="token operator">= class="tags" href="/C.html" title=c >c lass="token string">"hello" class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token c lass="tags" href="/C.html" title=c >c omment">// 转换为小写 class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">transform class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">begin class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">, sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">end class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">, sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">begin class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">, class="tags" href="/C.html" title=c >c lass="token double-c lass="tags" href="/C.html" title=c >c olon punc lass="tags" href="/C.html" title=c >c tuation">:: tolowerclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">transform class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( strclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">begin class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">, strclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">end class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">, strclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">begin class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">, class="tags" href="/C.html" title=c >c lass="token double-c lass="tags" href="/C.html" title=c >c olon punc lass="tags" href="/C.html" title=c >c tuation">:: tolowerclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; size_t pos class="tags" href="/C.html" title=c >c lass="token operator">= sclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">. class="tags" href="/C.html" title=c >c lass="token func lass="tags" href="/C.html" title=c >c tion">find class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( strclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token keyword">if class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">( pos class="tags" href="/C.html" title=c >c lass="token operator">!= stringclass="tags" href="/C.html" title=c >c lass="token double-c lass="tags" href="/C.html" title=c >c olon punc lass="tags" href="/C.html" title=c >c tuation">:: nposclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">) class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">{ c lass="tags" href="/C.html" title=c >c out class="tags" href="/C.html" title=c >c lass="token operator"><< class="tags" href="/C.html" title=c >c lass="token string">"找到c lass="tags" href="/C.html" title=c >c ;位置是：" class="tags" href="/C.html" title=c >c lass="token operator"><< pos class="tags" href="/C.html" title=c >c lass="token operator"><< endlclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">} class="tags" href="/C.html" title=c >c lass="token keyword">else class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">{ c lass="tags" href="/C.html" title=c >c out class="tags" href="/C.html" title=c >c lass="token operator"><< class="tags" href="/C.html" title=c >c lass="token string">"没有找到" class="tags" href="/C.html" title=c >c lass="token operator"><< endlclass="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">; class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">} class="tags" href="/C.html" title=c >c lass="token keyword">return class="tags" href="/C.html" title=c >c lass="token number">0 class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">;
class="tags" href="/C.html" title=c >c lass="token punc lass="tags" href="/C.html" title=c >c tuation">}
class="tags" href="/C.html" title=c >c ode>
输出：
<c lass="tags" href="/C.html" title=c >c ode>找到c lass="tags" href="/C.html" title=c >c ;位置是：0
class="tags" href="/C.html" title=c >c ode>
C++ 中的 <c lass="tags" href="/C.html" title=c >c ode>find()class="tags" href="/C.html" title=c >c ode> 函数是字符串操作中极其重要的工具。通过对其多种使用方法的学习c lass="tags" href="/C.html" title=c >c ;我们可以解决多种字符串匹配问题：
基本查找功能c lass="tags" href="/C.html" title=c >c ;用于快速定位子串或字符； 通过 <c lass="tags" href="/C.html" title=c >c ode>nposclass="tags" href="/C.html" title=c >c ode> 判断查找失败c lass="tags" href="/C.html" title=c >c ;确保程序稳定性； 结合循环c lass="tags" href="/C.html" title=c >c ;实现多次查找或全文匹配； 配合 <c lass="tags" href="/C.html" title=c >c ode>substr()class="tags" href="/C.html" title=c >c ode> 等函数c lass="tags" href="/C.html" title=c >c ;提取匹配上下文。 此外c lass="tags" href="/C.html" title=c >c ;在实际开发中c lass="tags" href="/C.html" title=c >c ;还可以通过忽略大小写等变形用法来满足不同场景需求。希望本文能够帮助读者深入理解并熟练掌握 <c lass="tags" href="/C.html" title=c >c ode>find()class="tags" href="/C.html" title=c >c ode> 函数的使用。
c >c ="https://img-blog.c lass="tags" href="/C.html" title=c >c sdnimg.c lass="tags" href="/C.html" title=c >c n/direc lass="tags" href="/C.html" title=c >c t/00d4fdeb7b0d4dbb99e88f325ef249d8.gif#pic lass="tags" href="/C.html" title=c >c _c lass="tags" href="/C.html" title=c >c enter" alt="在这里插入图片描述" width="1000" height="100" />
c >c ="https://i-blog.c lass="tags" href="/C.html" title=c >c sdnimg.c lass="tags" href="/C.html" title=c >c n/direc lass="tags" href="/C.html" title=c >c t/fc lass="tags" href="/C.html" title=c >c 6ac lass="tags" href="/C.html" title=c >c 6d93b4745b591bb8a8e48f86779.png#pic lass="tags" href="/C.html" title=c >c _right" alt="在这里插入图片描述" width="1" />c >c ="https://i-blog.c lass="tags" href="/C.html" title=c >c sdnimg.c lass="tags" href="/C.html" title=c >c n/direc lass="tags" href="/C.html" title=c >c t/fc lass="tags" href="/C.html" title=c >c 6ac lass="tags" href="/C.html" title=c >c 6d93b4745b591bb8a8e48f86779.png#pic lass="tags" href="/C.html" title=c >c _right" alt="在这里插入图片描述" width="1" />c >c ="https://i-blog.c lass="tags" href="/C.html" title=c >c sdnimg.c lass="tags" href="/C.html" title=c >c n/direc lass="tags" href="/C.html" title=c >c t/fc lass="tags" href="/C.html" title=c >c 6ac lass="tags" href="/C.html" title=c >c 6d93b4745b591bb8a8e48f86779.png#pic lass="tags" href="/C.html" title=c >c _right" alt="在这里插入图片描述" width="1" />c >c ="https://i-blog.c lass="tags" href="/C.html" title=c >c sdnimg.c lass="tags" href="/C.html" title=c >c n/direc lass="tags" href="/C.html" title=c >c t/fc lass="tags" href="/C.html" title=c >c 6ac lass="tags" href="/C.html" title=c >c 6d93b4745b591bb8a8e48f86779.png#pic lass="tags" href="/C.html" title=c >c _right" alt="在这里插入图片描述" width="1" />c >c ="https://i-blog.c lass="tags" href="/C.html" title=c >c sdnimg.c lass="tags" href="/C.html" title=c >c n/direc lass="tags" href="/C.html" title=c >c t/fc lass="tags" href="/C.html" title=c >c 6ac lass="tags" href="/C.html" title=c >c 6d93b4745b591bb8a8e48f86779.png#pic lass="tags" href="/C.html" title=c >c _right" alt="在这里插入图片描述" width="1" />c >c ="https://i-blog.c lass="tags" href="/C.html" title=c >c sdnimg.c lass="tags" href="/C.html" title=c >c n/direc lass="tags" href="/C.html" title=c >c t/fc lass="tags" href="/C.html" title=c >c 6ac lass="tags" href="/C.html" title=c >c 6d93b4745b591bb8a8e48f86779.png#pic lass="tags" href="/C.html" title=c >c _right" alt="在这里插入图片描述" width="1" />c >c ="https://i-blog.c lass="tags" href="/C.html" title=c >c sdnimg.c lass="tags" href="/C.html" title=c >c n/direc lass="tags" href="/C.html" title=c >c t/fc lass="tags" href="/C.html" title=c >c 6ac lass="tags" href="/C.html" title=c >c 6d93b4745b591bb8a8e48f86779.png#pic lass="tags" href="/C.html" title=c >c _right" alt="在这里插入图片描述" width="1" />c >c ="https://i-blog.c lass="tags" href="/C.html" title=c >c sdnimg.c lass="tags" href="/C.html" title=c >c n/direc lass="tags" href="/C.html" title=c >c t/fc lass="tags" href="/C.html" title=c >c 6ac lass="tags" href="/C.html" title=c >c 6d93b4745b591bb8a8e48f86779.png#pic lass="tags" href="/C.html" title=c >c _right" alt="在这里插入图片描述" width="1" />c >c ="https://i-blog.c lass="tags" href="/C.html" title=c >c sdnimg.c lass="tags" href="/C.html" title=c >c n/direc lass="tags" href="/C.html" title=c >c t/fc lass="tags" href="/C.html" title=c >c 6ac lass="tags" href="/C.html" title=c >c 6d93b4745b591bb8a8e48f86779.png#pic lass="tags" href="/C.html" title=c >c _right" alt="在这里插入图片描述" width="1" />c >c ="https://i-blog.c lass="tags" href="/C.html" title=c >c sdnimg.c lass="tags" href="/C.html" title=c >c n/direc lass="tags" href="/C.html" title=c >c t/fc lass="tags" href="/C.html" title=c >c 6ac lass="tags" href="/C.html" title=c >c 6d93b4745b591bb8a8e48f86779.png#pic lass="tags" href="/C.html" title=c >c _right" alt="在这里插入图片描述" width="1" />
学习C++的建议
C++ 是一门强大且广泛应用的编程语言c lass="tags" href="/C.html" title=c >c ;无论是系统开发、游戏开发还是高性能计算c lass="tags" href="/C.html" title=c >c ;它都有不可替代的地位。然而c lass="tags" href="/C.html" title=c >c ;学习C++的道路可能是陡峭的c lass="tags" href="/C.html" title=c >c ;为了帮助你更高效地掌握这门语言c lass="tags" href="/C.html" title=c >c ;我总结了一些学习建议和经验。
1. 理解C++的基础 学习重点：
掌握基本语法 ： 学会声明变量、条件语句、循环、函数等核心语法。 掌握数组、指针、引用等基础知识。 熟悉标准输入输出 ： 掌握 <c lass="tags" href="/C.html" title=c >c ode>c lass="tags" href="/C.html" title=c >c inclass="tags" href="/C.html" title=c >c ode> 和 <c lass="tags" href="/C.html" title=c >c ode>c lass="tags" href="/C.html" title=c >c outclass="tags" href="/C.html" title=c >c ode> 的用法。 理解格式化输出c lass="tags" href="/C.html" title=c >c ;例如 <c lass="tags" href="/C.html" title=c >c ode>std::setwclass="tags" href="/C.html" title=c >c ode> 和 <c lass="tags" href="/C.html" title=c >c ode>std::fixedclass="tags" href="/C.html" title=c >c ode>。 记住编译器的角色 ： 理解源代码如何通过编译器转换为可执行程序c lass="tags" href="/C.html" title=c >c ;选择一款好的IDE（如Visual Studio、Clion、VSCode）。 class="tags" href="/C.html" title=c >c kquote> 建议 ：用大量小程序练习这些基础语法c lass="tags" href="/C.html" title=c >c ;比如写一个计算器、模拟猜数字游戏等。
class="tags" href="/C.html" title=
c >
c kquote>
2. 深入学习C++的特性 学习重点：
面向对象编程（OOP） ： 理解类和对象c lass="tags" href="/C.html" title=c >c ;熟悉如何定义类、成员变量和成员函数。 掌握封装、继承、多态三大核心特性。 内存管理 ： 理解指针的用法c lass="tags" href="/C.html" title=c >c ;掌握动态内存分配（<c lass="tags" href="/C.html" title=c >c ode>newclass="tags" href="/C.html" title=c >c ode> 和 <c lass="tags" href="/C.html" title=c >c ode>deleteclass="tags" href="/C.html" title=c >c ode>）。 学习如何避免内存泄漏c lass="tags" href="/C.html" title=c >c ;熟悉智能指针（如<c lass="tags" href="/C.html" title=c >c ode>std::unique_ptrclass="tags" href="/C.html" title=c >c ode> 和 <c lass="tags" href="/C.html" title=c >c ode>std::shared_ptrclass="tags" href="/C.html" title=c >c ode>）。 标准模板库（STL） ： 熟悉常用的容器（如<c lass="tags" href="/C.html" title=c >c ode>vec lass="tags" href="/C.html" title=c >c torclass="tags" href="/C.html" title=c >c ode>、<c lass="tags" href="/C.html" title=c >c ode>mapclass="tags" href="/C.html" title=c >c ode>、<c lass="tags" href="/C.html" title=c >c ode>setclass="tags" href="/C.html" title=c >c ode>）和算法（如<c lass="tags" href="/C.html" title=c >c ode>sortclass="tags" href="/C.html" title=c >c ode>、<c lass="tags" href="/C.html" title=c >c ode>findclass="tags" href="/C.html" title=c >c ode>）。 掌握迭代器的用法。 异常处理 ： 学习使用<c lass="tags" href="/C.html" title=c >c ode>try-c lass="tags" href="/C.html" title=c >c atc lass="tags" href="/C.html" title=c >c hclass="tags" href="/C.html" title=c >c ode>块处理异常。 理解异常的用途以及如何设计健壮的代码。 class="tags" href="/C.html" title=c >c kquote> 建议 ：尝试开发一个小型项目c lass="tags" href="/C.html" title=c >c ;比如一个学生管理系统c lass="tags" href="/C.html" title=c >c ;综合应用类、STL、指针和动态内存分配。
class="tags" href="/C.html" title=
c >
c kquote>
3. 掌握进阶内容 学习重点：
模板 ： 理解函数模板和类模板c lass="tags" href="/C.html" title=c >c ;掌握泛型编程思想。 学习模板特化和模板元编程的基本概念。 多线程与并发 ： 学习 C++11 提供的多线程支持（如<c lass="tags" href="/C.html" title=c >c ode>std::threadclass="tags" href="/C.html" title=c >c ode>）。 熟悉互斥锁（<c lass="tags" href="/C.html" title=c >c ode>std::mutexclass="tags" href="/C.html" title=c >c ode>）和条件变量（<c lass="tags" href="/C.html" title=c >c ode>std::c lass="tags" href="/C.html" title=c >c ondition_variableclass="tags" href="/C.html" title=c >c ode>）。 C++与C的兼容性 ： 学习如何在C++中使用C语言代码c lass="tags" href="/C.html" title=c >c ;理解C和C++的区别。 掌握C风格字符串（<c lass="tags" href="/C.html" title=c >c ode>c lass="tags" href="/C.html" title=c >c har[]class="tags" href="/C.html" title=c >c ode>）和C++字符串（<c lass="tags" href="/C.html" title=c >c ode>std::stringclass="tags" href="/C.html" title=c >c ode>）的转换。 class="tags" href="/C.html" title=c >c kquote> 建议 ：在这一阶段c lass="tags" href="/C.html" title=c >c ;可以挑战更复杂的项目c lass="tags" href="/C.html" title=c >c ;比如开发一个小型的HTTP服务器c lass="tags" href="/C.html" title=c >c ;学习网络编程并结合多线程。
class="tags" href="/C.html" title=
c >
c kquote>
4. 学习资源与实践方法 学习资源：
书籍 ： 《C++ Primer》：非常适合初学者的经典书籍。 《Effec lass="tags" href="/C.html" title=c >c tive C++》：进阶学习C++最佳实践的指南。 《The C++ Programming Language》：Bjarne Stroustrup（C++之父）的权威著作。 在线课程 ： Coursera 上的 C++ 编程课程。 YouTube 上免费的 C++ 系列教程。 社区与文档 ： 参与C++相关的论坛（如CSDN、Stac lass="tags" href="/C.html" title=c >c k Overflow）。 阅读官方文档（https://en.c lass="tags" href="/C.html" title=c >c ppreferenc lass="tags" href="/C.html" title=c >c e.c lass="tags" href="/C.html" title=c >c om）。 实践方法：
多写代码c lass="tags" href="/C.html" title=c >c ;多调试 ： 每学一个概念后c lass="tags" href="/C.html" title=c >c ;写至少两个示例代码并进行调试。 做小项目 ： 从简单的控制台程序开始c lass="tags" href="/C.html" title=c >c ;比如文件读写、计算器、小游戏等。 慢慢过渡到图形界面或网络程序开发。 阅读他人代码 ： 阅读开源项目的代码c lass="tags" href="/C.html" title=c >c ;理解优秀代码的设计思路。 参加编程比赛 ： 比如 LeetCode 或 Codeforc lass="tags" href="/C.html" title=c >c esc lass="tags" href="/C.html" title=c >c ;可以帮助你提升算法能力和C++的熟练度。 5. 保持耐心与兴趣
复杂的语法 ：如模板、智能指针、多线程等。调试困难 ：指针错误、内存泄漏、未定义行为可能让人头疼。如何应对：
将大问题拆解成小问题c lass="tags" href="/C.html" title=c >c ;逐步解决。 不断重复基础知识c lass="tags" href="/C.html" title=c >c ;以加深理解。 保持兴趣c lass="tags" href="/C.html" title=c >c ;尝试一些有趣的项目c lass="tags" href="/C.html" title=c >c ;比如写一个游戏、制作一个简单的图形程序。 小结 c lass="tags" href="/C.html" title=c >c ;从基础语法到面向对象编程c lass="tags" href="/C.html" title=c >c ;再到进阶的模板和并发编程c lass="tags" href="/C.html" title=c >c ;每一步都需要耐心和实践。通过充分利用学习资源、进行大量编码练习c lass="tags" href="/C.html" title=c >c ;以及挑战实际项目c lass="tags" href="/C.html" title=c >c ;你一定可以成为C++的高手。记住c lass="tags" href="/C.html" title=c >c ;学习的核心在于理解c lass="tags" href="/C.html" title=c >c ;而非死记硬背。
祝你学有所成c lass="tags" href="/C.html" title=c >c ;享受C++编程的乐趣！
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