320 lines
34 KiB
HTML
320 lines
34 KiB
HTML
<!DOCTYPE html>
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<html lang="zh" dir="ltr" class="client-nojs" xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh">
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<title>std::ranges::find_end</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_algorithm_ranges_find_end skin-cppreference2 action-view cpp-navbar">
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::ranges::</span>find_end</h1>
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<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-algorithm.html">algorithm</a>‎ | <a href="cpp-algorithm-ranges.html">ranges</a></span></div>
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<div id="mw-content-text" lang="zh" dir="ltr" class="mw-content-ltr" xml:lang="zh">
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<table class="t-dcl-begin">
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<div>定义于头文件 <code><a href="cpp-header-algorithm.html"><algorithm></a></code></div>
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<td></td>
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<div>调用签名</div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> std<span class="sy4">::</span><span class="me2">forward_iterator</span> I1, std<span class="sy4">::</span><span class="me2">sentinel_for</span><span class="sy1"><</span>I1<span class="sy1">></span> S1,<br /></span>
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<p> std<span class="sy4">::</span><span class="me2">forward_iterator</span> I2, std<span class="sy4">::</span><span class="me2">sentinel_for</span><span class="sy1"><</span>I2<span class="sy1">></span> S2,<br />
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<span class="kw1">class</span> Pred <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">equal_to</span>,<br />
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<span class="kw1">class</span> Proj1 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span>,<br />
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<span class="kw1">class</span> Proj2 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span> <span class="sy1">></span><br />
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requires std<span class="sy4">::</span><span class="me2">indirectly_comparable</span><span class="sy1"><</span>I1, I2, Pred, Proj1, Proj2<span class="sy1">></span><br />
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<span class="kw4">constexpr</span> ranges<span class="sy4">::</span><span class="me2">subrange</span><span class="sy1"><</span>I1<span class="sy1">></span><br />
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find_end<span class="br0">(</span> I1 first1, S1 last1, I2 first2, S2 last2,<br /></p>
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Pred pred <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>, Proj1 proj1 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>, Proj2 proj2 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span> <span class="br0">)</span><span class="sy4">;</span></div>
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</td>
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<td>(1)</td>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> ranges<span class="sy4">::</span><span class="me2">forward_range</span> R1, ranges<span class="sy4">::</span><span class="me2">forward_range</span> R2,<br /></span>
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<p> <span class="kw1">class</span> Pred <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">equal_to</span>,<br />
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<span class="kw1">class</span> Proj1 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span>,<br />
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<span class="kw1">class</span> Proj2 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span> <span class="sy1">></span><br />
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requires std<span class="sy4">::</span><span class="me2">indirectly_comparable</span><span class="sy1"><</span>ranges<span class="sy4">::</span><span class="me2">iterator_t</span><span class="sy1"><</span>R1<span class="sy1">></span>,<br />
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ranges<span class="sy4">::</span><span class="me2">iterator_t</span><span class="sy1"><</span>R2<span class="sy1">></span>,<br />
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Pred, Proj1, Proj2<span class="sy1">></span><br />
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<span class="kw4">constexpr</span> ranges<span class="sy4">::</span><span class="me2">borrowed_subrange_t</span><span class="sy1"><</span>R1<span class="sy1">></span><br />
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find_end<span class="br0">(</span> R1<span class="sy3">&&</span> r1, R2<span class="sy3">&&</span> r2, Pred pred <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>,<br /></p>
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Proj1 proj1 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>, Proj2 proj2 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span> <span class="br0">)</span><span class="sy4">;</span></div>
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</td>
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<td>(2)</td>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span></td>
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</tr>
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<td></td>
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<div class="t-li1"><span class="t-li">1)</span> 搜索序列 <code>[first2, last2)</code> 在范围 <code>[first1, last1)</code> 中的<i>最后</i>出现，在分别以<span class="t-c"><span class="mw-geshi cpp source-cpp">proj1</span></span> 与 <span class="t-c"><span class="mw-geshi cpp source-cpp">proj2</span></span> 投影后。用二元谓词 <code>pred</code> 比较投影后的元素。</div>
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<div class="t-li1"><span class="t-li">2)</span> 同 <span class="t-v">(1)</span> ，但以 <code>r1</code> 为第一源范围并以 <code>r2</code> 为第二源范围，如同以 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">begin</span><span class="br0">(</span>r1<span class="br0">)</span></span></span> 为 <code>first1</code> ，以 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">end</span><span class="br0">(</span>r1<span class="br0">)</span></span></span> 为 <code>last1</code> ， <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">begin</span><span class="br0">(</span>r2<span class="br0">)</span></span></span> 为 <code>first2</code> ，并以 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">end</span><span class="br0">(</span>r2<span class="br0">)</span></span></span> 为 <code>last2</code> 。</div>
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<p>此页面上描述的仿函数实体是 <i>niebloid</i> ，即：</p>
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<ul>
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<li>调用它们中的任何一者时不可指定显式模板实参。</li>
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<li>它们无一对<a href="cpp-language-adl.html">实参依赖查找</a>可见。</li>
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<li>在<a href="cpp-language-unqualified_lookup.html">通常无限定查找</a>寻找函数调用运算符左侧的名称找到它们之一时，它禁止<a href="cpp-language-adl.html">实参依赖查找</a>。</li>
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</ul>
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<p>实际上，它们能以函数对象，或以某些特殊编译器扩展实现。</p>
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<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">参数</span></h3>
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<table class="t-par-begin">
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<tr class="t-par">
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<td>first1, last1</td>
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<td>-</td>
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<td>要检验的元素范围（又称<i>草堆</i>）</td>
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</tr>
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<tr class="t-par">
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<td>first2, last2</td>
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<td>-</td>
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<td>要搜索的元素范围（又称<i>针</i>）</td>
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</tr>
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<tr class="t-par">
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<td>r1</td>
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<td>-</td>
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<td>要检验的元素范围（又称<i>草堆</i>）</td>
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</tr>
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<tr class="t-par">
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<td>r2</td>
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<td>-</td>
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<td>要搜索的元素范围（又称<i>针</i>）</td>
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</tr>
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<tr class="t-par">
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<td>pred</td>
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<td>-</td>
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<td>比较元素的二元谓词</td>
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</tr>
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<tr class="t-par">
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<td>proj1</td>
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<td>-</td>
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<td>应用到第一范围中元素的投影</td>
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</tr>
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<tr class="t-par">
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<td>proj2</td>
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<td>-</td>
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<td>应用到第二范围中元素的投影</td>
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</tr>
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</table>
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<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">返回值</span></h3>
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<div class="t-li1"><span class="t-li">1)</span> 以表达式 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="br0">{</span>i, i <span class="sy2">+</span> <span class="br0">(</span>i <span class="sy1">==</span> last1 <span class="sy4">?</span> <span class="nu0">0</span> <span class="sy4">:</span> last2 <span class="sy2">-</span> first2<span class="br0">)</span><span class="br0">}</span></span></span> 初始化的 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">subrange</span><span class="sy1"><</span>I1<span class="sy1">></span></span></span> 值，该范围代表序列 <code>[first2, last2)</code> 在范围 <code>[first1, last1)</code> 中的最后一次出现（在以 <span class="t-c"><span class="mw-geshi cpp source-cpp">proj1</span></span> 与 <span class="t-c"><span class="mw-geshi cpp source-cpp">proj2</span></span> 投影后）。若 <code>[first2, last2)</code> 为空或找不到该序列，则等效地以 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="br0">{</span>last1, last1<span class="br0">}</span></span></span> 初始化返回值。</div>
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<div class="t-li1"><span class="t-li">2)</span> 同 <span class="t-v">(1)</span> ，除了返回类型为 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">borrowed_subrange_t</span><span class="sy1"><</span>R1<span class="sy1">></span></span></span> 。</div>
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<h3><span class="mw-headline" id=".E5.A4.8D.E6.9D.82.E5.BA.A6">复杂度</span></h3>
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<p>至多应用 <span class="mjax" style="display:none">\(\scriptsize S\cdot(N-S+1)\)</span><span class="mjax-fallback texhtml" style="white-space: nowrap;">S·(N-S+1)</span> 次谓词和对应的每次投影，其中对于 <span class="t-v">(1)</span> <span class="mjax" style="display:none">\(\scriptsize S\)</span><span class="mjax-fallback texhtml" style="white-space: nowrap;">S</span> 为 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">distance</span><span class="br0">(</span>first2, last2<span class="br0">)</span></span></span> 而 <span class="mjax" style="display:none">\(\scriptsize N\)</span><span class="mjax-fallback texhtml" style="white-space: nowrap;">N</span> 为 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">distance</span><span class="br0">(</span>first1, last1<span class="br0">)</span></span></span> ，或对于 <span class="t-v">(2)</span> <span class="mjax" style="display:none">\(\scriptsize S\)</span><span class="mjax-fallback texhtml" style="white-space: nowrap;">S</span> 为 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">distance</span><span class="br0">(</span>r2<span class="br0">)</span></span></span> 而 <span class="mjax" style="display:none">\(\scriptsize N\)</span><span class="mjax-fallback texhtml" style="white-space: nowrap;">N</span> 为 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">distance</span><span class="br0">(</span>r1<span class="br0">)</span></span></span> 。</p>
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<h3><span class="mw-headline" id=".E6.B3.A8.E8.A7.A3">注解</span></h3>
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<p>若输入迭代器实现 <span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">bidirectional_iterator</span></span></span> ，则实现可以通过从末尾到起始搜索改进效率。实现 <span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">random_access_iterator</span></span></span> 可能提升比较速度。然而所有这些不改变最坏情况的理论复杂度。</p>
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<h3><span class="mw-headline" id=".E5.8F.AF.E8.83.BD.E7.9A.84.E5.AE.9E.E7.8E.B0">可能的实现</span></h3>
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<table class="eq-fun-cpp-table">
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<tr>
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<div dir="ltr" class="mw-geshi" style="text-align: left;">
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<div class="cpp source-cpp">
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<pre class="de1"><span class="kw1">struct</span> find_end_fn <span class="br0">{</span>
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<span class="kw1">template</span><span class="sy1"><</span>std<span class="sy4">::</span><span class="me2">forward_iterator</span> I1, std<span class="sy4">::</span><span class="me2">sentinel_for</span><span class="sy1"><</span>I1<span class="sy1">></span> S1,
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std<span class="sy4">::</span><span class="me2">forward_iterator</span> I2, std<span class="sy4">::</span><span class="me2">sentinel_for</span><span class="sy1"><</span>I2<span class="sy1">></span> S2,
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<span class="kw1">class</span> Pred <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">equal_to</span>,
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<span class="kw1">class</span> Proj1 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span>, <span class="kw1">class</span> Proj2 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span><span class="sy1">></span>
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requires std<span class="sy4">::</span><span class="me2">indirectly_comparable</span><span class="sy1"><</span>I1, I2, Pred, Proj1, Proj2<span class="sy1">></span>
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<span class="kw4">constexpr</span> ranges<span class="sy4">::</span><span class="me2">subrange</span><span class="sy1"><</span>I1<span class="sy1">></span>
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operator<span class="br0">(</span><span class="br0">)</span><span class="br0">(</span>I1 first1, S1 last1,
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I2 first2, S2 last2, Pred pred <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>,
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Proj1 proj1 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>, Proj2 proj2 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span><span class="br0">)</span> <span class="kw4">const</span>
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<span class="br0">{</span>
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<span class="kw1">if</span> <span class="br0">(</span>first2 <span class="sy1">==</span> last2<span class="br0">)</span> <span class="br0">{</span>
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<span class="kw4">auto</span> last_it <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">next</span><span class="br0">(</span>first1, last1<span class="br0">)</span><span class="sy4">;</span>
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<span class="kw1">return</span> <span class="br0">{</span>last_it, last_it<span class="br0">}</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="kw4">auto</span> result <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">search</span><span class="br0">(</span>
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std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>first1<span class="br0">)</span>, last1, first2, last2, pred, proj1, proj2<span class="br0">)</span><span class="sy4">;</span>
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<span class="kw1">if</span> <span class="br0">(</span>result.<span class="me1">empty</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span> <span class="kw1">return</span> result<span class="sy4">;</span>
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<span class="kw1">for</span> <span class="br0">(</span><span class="sy4">;;</span><span class="br0">)</span> <span class="br0">{</span>
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<span class="kw4">auto</span> new_result <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">search</span><span class="br0">(</span>
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<a href="cpp-iterator-next.html"><span class="kw674">std::<span class="me2">next</span></span></a><span class="br0">(</span>result.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span>, last1, first2, last2, pred, proj1, proj2<span class="br0">)</span><span class="sy4">;</span>
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<span class="kw1">if</span> <span class="br0">(</span>new_result.<span class="me1">empty</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span>
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<span class="kw1">return</span> result<span class="sy4">;</span>
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<span class="kw1">else</span>
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result <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>new_result<span class="br0">)</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="br0">}</span>
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<span class="kw1">template</span><span class="sy1"><</span>ranges<span class="sy4">::</span><span class="me2">forward_range</span> R1, ranges<span class="sy4">::</span><span class="me2">forward_range</span> R2,
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<span class="kw1">class</span> Pred <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">equal_to</span>,
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<span class="kw1">class</span> Proj1 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span>,
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<span class="kw1">class</span> Proj2 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span><span class="sy1">></span>
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requires std<span class="sy4">::</span><span class="me2">indirectly_comparable</span><span class="sy1"><</span>ranges<span class="sy4">::</span><span class="me2">iterator_t</span><span class="sy1"><</span>R1<span class="sy1">></span>,
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ranges<span class="sy4">::</span><span class="me2">iterator_t</span><span class="sy1"><</span>R2<span class="sy1">></span>,
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Pred, Proj1, Proj2<span class="sy1">></span>
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<span class="kw4">constexpr</span> ranges<span class="sy4">::</span><span class="me2">borrowed_subrange_t</span><span class="sy1"><</span>R1<span class="sy1">></span>
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operator<span class="br0">(</span><span class="br0">)</span><span class="br0">(</span>R1<span class="sy3">&&</span> r1, R2<span class="sy3">&&</span> r2, Pred pred <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>,
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Proj1 proj1 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>, Proj2 proj2 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span><span class="br0">)</span> <span class="kw4">const</span>
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<span class="br0">{</span>
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<span class="kw1">return</span> <span class="br0">(</span><span class="sy2">*</span>this<span class="br0">)</span><span class="br0">(</span>ranges<span class="sy4">::</span><span class="me2">begin</span><span class="br0">(</span>r1<span class="br0">)</span>, ranges<span class="sy4">::</span><span class="me2">end</span><span class="br0">(</span>r1<span class="br0">)</span>,
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ranges<span class="sy4">::</span><span class="me2">begin</span><span class="br0">(</span>r2<span class="br0">)</span>, ranges<span class="sy4">::</span><span class="me2">end</span><span class="br0">(</span>r2<span class="br0">)</span>,
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std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>pred<span class="br0">)</span>,
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std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>proj1<span class="br0">)</span>, std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>proj2<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="br0">}</span><span class="sy4">;</span>
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<span class="kw1">inline</span> <span class="kw4">constexpr</span> find_end_fn find_end<span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span></pre></div>
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</div>
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</td>
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</tr>
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</table>
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<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">示例</span></h3>
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<div class="t-example">
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<div class="t-example-live-link"></div>
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<div dir="ltr" class="mw-geshi" style="text-align: left;">
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<div class="cpp source-cpp">
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<pre class="de1"><span class="co2">#include <algorithm></span>
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<span class="co2">#include <array></span>
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<span class="co2">#include <cctype></span>
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<span class="co2">#include <iostream></span>
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<span class="co2">#include <ranges></span>
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<span class="co2">#include <string_view></span>
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<span class="kw4">void</span> print<span class="br0">(</span><span class="kw4">const</span> <span class="kw4">auto</span> haystack, <span class="kw4">const</span> <span class="kw4">auto</span> needle<span class="br0">)</span>
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<span class="br0">{</span>
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<span class="kw4">const</span> <span class="kw4">auto</span> pos <span class="sy1">=</span> <a href="cpp-iterator-distance.html"><span class="kw673">std::<span class="me2">distance</span></span></a><span class="br0">(</span>haystack.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span>, needle.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"In <span class="es1">\"</span>"</span><span class="sy4">;</span>
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<span class="kw1">for</span> <span class="br0">(</span><span class="kw4">const</span> <span class="kw4">auto</span> c <span class="sy4">:</span> haystack<span class="br0">)</span> <span class="br0">{</span> <a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> c<span class="sy4">;</span> <span class="br0">}</span>
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<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"<span class="es1">\"</span> found <span class="es1">\"</span>"</span><span class="sy4">;</span>
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<span class="kw1">for</span> <span class="br0">(</span><span class="kw4">const</span> <span class="kw4">auto</span> c <span class="sy4">:</span> needle<span class="br0">)</span> <span class="br0">{</span> <a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> c<span class="sy4">;</span> <span class="br0">}</span>
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<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"<span class="es1">\"</span> at position ["</span> <span class="sy1"><<</span> pos <span class="sy1"><<</span> <span class="st0">".."</span> <span class="sy1"><<</span> pos <span class="sy2">+</span> needle.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">")<span class="es1">\n</span>"</span>
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<span class="sy1"><<</span> <a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a><span class="br0">(</span><span class="nu0">4</span> <span class="sy2">+</span> pos, <span class="st0">' '</span><span class="br0">)</span> <span class="sy1"><<</span> <a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a><span class="br0">(</span>needle.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span>, <span class="st0">'^'</span><span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
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<span class="br0">{</span>
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<span class="kw1">using</span> <span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">literals</span><span class="sy4">;</span>
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<span class="kw4">constexpr</span> <span class="kw4">auto</span> secret<span class="br0">{</span><span class="st0">"password password word..."</span>sv<span class="br0">}</span><span class="sy4">;</span>
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<span class="kw4">constexpr</span> <span class="kw4">auto</span> wanted<span class="br0">{</span><span class="st0">"password"</span>sv<span class="br0">}</span><span class="sy4">;</span>
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<span class="kw4">constexpr</span> <span class="kw4">auto</span> found1 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">find_end</span><span class="br0">(</span>
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secret.<span class="me1">cbegin</span><span class="br0">(</span><span class="br0">)</span>, secret.<span class="me1">cend</span><span class="br0">(</span><span class="br0">)</span>, wanted.<span class="me1">cbegin</span><span class="br0">(</span><span class="br0">)</span>, wanted.<span class="me1">cend</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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print<span class="br0">(</span>secret, found1<span class="br0">)</span><span class="sy4">;</span>
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<span class="kw4">constexpr</span> <span class="kw4">auto</span> found2 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">find_end</span><span class="br0">(</span>secret, <span class="st0">"word"</span>sv<span class="br0">)</span><span class="sy4">;</span>
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print<span class="br0">(</span>secret, found2<span class="br0">)</span><span class="sy4">;</span>
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<span class="kw4">const</span> <span class="kw4">auto</span> found3 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">find_end</span><span class="br0">(</span>secret, <span class="st0">"ORD"</span>sv,
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<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span><span class="kw4">const</span> <span class="kw4">char</span> x, <span class="kw4">const</span> <span class="kw4">char</span> y<span class="br0">)</span> <span class="br0">{</span> <span class="co1">// 用二元谓词</span>
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<span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">tolower</span><span class="br0">(</span>x<span class="br0">)</span> <span class="sy1">==</span> std<span class="sy4">::</span><span class="me2">tolower</span><span class="br0">(</span>y<span class="br0">)</span><span class="sy4">;</span>
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<span class="br0">}</span><span class="br0">)</span><span class="sy4">;</span>
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print<span class="br0">(</span>secret, found3<span class="br0">)</span><span class="sy4">;</span>
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<span class="kw4">const</span> <span class="kw4">auto</span> found4 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">find_end</span><span class="br0">(</span>secret, <span class="st0">"SWORD"</span>sv, <span class="br0">{</span><span class="br0">}</span>, <span class="br0">{</span><span class="br0">}</span>,
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|
<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span><span class="kw4">char</span> c<span class="br0">)</span> <span class="br0">{</span> <span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">tolower</span><span class="br0">(</span>c<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// 投影第二范围</span>
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print<span class="br0">(</span>secret, found4<span class="br0">)</span><span class="sy4">;</span>
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|
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|
static_assert<span class="br0">(</span>std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">find_end</span><span class="br0">(</span>secret, <span class="st0">"PASS"</span>sv<span class="br0">)</span>.<span class="me1">empty</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// => 找不到</span>
|
|
<span class="br0">}</span></pre></div>
|
|
</div>
|
|
<p>输出：</p>
|
|
<div dir="ltr" class="mw-geshi" style="text-align: left;">
|
|
<div class="text source-text">
|
|
<pre class="de1">In "password password word..." found "password" at position [9..17)
|
|
^^^^^^^^
|
|
In "password password word..." found "word" at position [18..22)
|
|
^^^^
|
|
In "password password word..." found "ord" at position [19..22)
|
|
^^^
|
|
In "password password word..." found "sword" at position [12..17)
|
|
^^^^^</pre></div>
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</div>
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</div>
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<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
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|
<table class="t-dsc-begin">
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|
<tr class="t-dsc">
|
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<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-find_end.html"><span class="t-lines"><span>find_end</span></span></a></div>
|
|
</div>
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</td>
|
|
<td>在特定范围中寻找最后出现的元素序列<br />
|
|
<span class="t-mark">(函数模板)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-ranges-adjacent_find.html"><span class="t-lines"><span>ranges::adjacent_find</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
|
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</div>
|
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</td>
|
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<td>查找首对相邻的相同（或满足给定谓词的）元素<br />
|
|
<span class="t-mark">(niebloid)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-ranges-find.html"><span class="t-lines"><span>ranges::find</span><span>ranges::find_if</span><span>ranges::find_if_not</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
|
|
</div>
|
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</td>
|
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<td>寻找首个满足特定判别标准的元素<br />
|
|
<span class="t-mark">(niebloid)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-ranges-find_first_of.html"><span class="t-lines"><span>ranges::find_first_of</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>搜索元素集合中的任一元素<br />
|
|
<span class="t-mark">(niebloid)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-ranges-search.html"><span class="t-lines"><span>ranges::search</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>搜索一个元素范围<br />
|
|
<span class="t-mark">(niebloid)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-ranges-search_n.html"><span class="t-lines"><span>ranges::search_n</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>在范围中搜索一定量的某个元素的连续副本<br />
|
|
<span class="t-mark">(niebloid)</span></td>
|
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</tr>
|
|
</table>
|
|
</div>
|
|
<div class="visualClear"></div>
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</div>
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</div>
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</div>
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</body>
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</html>
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