391 lines
30 KiB
HTML
391 lines
30 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::find, std::find_if, std::find_if_not</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_algorithm_find 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::</span>find, <span style="font-size:0.7em; line-height:130%">std::</span>find_if, <span style="font-size:0.7em; line-height:130%">std::</span>find_if_not</h1>
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<div id="bodyContent">
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<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-algorithm.html">algorithm</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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<tbody>
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<tr class="t-dsc-header">
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<td>
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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>
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<td></td>
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<td></td>
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</tbody>
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<tbody class="t-dcl-rev t-dcl-rev-num">
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<td></td>
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<td rowspan="142">(1)</td>
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<td></td>
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</tr>
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<tr class="t-dcl t-until-cxx20">
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> <span class="kw1">class</span> InputIt, <span class="kw1">class</span> T <span class="sy1">></span><br />
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InputIt find<span class="br0">(</span> InputIt first, InputIt last, <span class="kw4">const</span> T<span class="sy3">&</span> value <span class="br0">)</span><span class="sy4">;</span></span></div>
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</td>
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<td class="t-dcl-nopad"></td>
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<td><span class="t-mark-rev t-until-cxx20">(C++20 前)</span></td>
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</tr>
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<tr class="t-dcl t-since-cxx20">
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<td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> <span class="kw1">class</span> InputIt, <span class="kw1">class</span> T <span class="sy1">></span><br />
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<span class="kw4">constexpr</span> InputIt find<span class="br0">(</span> InputIt first, InputIt last, <span class="kw4">const</span> T<span class="sy3">&</span> value <span class="br0">)</span><span class="sy4">;</span></span></div>
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</td>
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<td class="t-dcl-nopad"></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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</tbody>
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<tbody>
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<tr class="t-dcl t-since-cxx17">
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<td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> <span class="kw1">class</span> ExecutionPolicy, <span class="kw1">class</span> ForwardIt, <span class="kw1">class</span> T <span class="sy1">></span><br /></span>
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<p>ForwardIt find<span class="br0">(</span> ExecutionPolicy<span class="sy3">&&</span> policy, ForwardIt first, ForwardIt last,<br /></p>
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<span class="kw4">const</span> T<span class="sy3">&</span> value <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-cxx17">(C++17 起)</span></td>
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</tr>
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</tbody>
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<tbody class="t-dcl-rev t-dcl-rev-num">
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<tr class="t-dcl-rev-aux">
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<td></td>
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<td rowspan="142">(3)</td>
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<td></td>
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</tr>
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<tr class="t-dcl t-until-cxx20">
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<td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> <span class="kw1">class</span> InputIt, <span class="kw1">class</span> UnaryPredicate <span class="sy1">></span><br /></span>
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<p>InputIt find_if<span class="br0">(</span> InputIt first, InputIt last,<br /></p>
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UnaryPredicate p <span class="br0">)</span><span class="sy4">;</span></div>
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</td>
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<td class="t-dcl-nopad"></td>
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<td><span class="t-mark-rev t-until-cxx20">(C++20 前)</span></td>
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</tr>
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<tr class="t-dcl t-since-cxx20">
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<td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> <span class="kw1">class</span> InputIt, <span class="kw1">class</span> UnaryPredicate <span class="sy1">></span><br /></span>
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<p><span class="kw4">constexpr</span> InputIt find_if<span class="br0">(</span> InputIt first, InputIt last,<br /></p>
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UnaryPredicate p <span class="br0">)</span><span class="sy4">;</span></div>
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</td>
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<td class="t-dcl-nopad"></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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</tbody>
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<tbody>
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<tr class="t-dcl t-since-cxx17">
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<td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> <span class="kw1">class</span> ExecutionPolicy, <span class="kw1">class</span> ForwardIt, <span class="kw1">class</span> UnaryPredicate <span class="sy1">></span><br /></span>
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<p>ForwardIt find_if<span class="br0">(</span> ExecutionPolicy<span class="sy3">&&</span> policy, ForwardIt first, ForwardIt last,<br /></p>
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UnaryPredicate p <span class="br0">)</span><span class="sy4">;</span></div>
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</td>
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<td>(4)</td>
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<td><span class="t-mark-rev t-since-cxx17">(C++17 起)</span></td>
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</tr>
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</tbody>
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<tbody class="t-dcl-rev t-dcl-rev-num">
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<tr class="t-dcl-rev-aux">
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<td></td>
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<td rowspan="142">(5)</td>
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<td></td>
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</tr>
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<tr class="t-dcl t-since-cxx11 t-until-cxx20">
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<td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> <span class="kw1">class</span> InputIt, <span class="kw1">class</span> UnaryPredicate <span class="sy1">></span><br /></span>
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<p>InputIt find_if_not<span class="br0">(</span> InputIt first, InputIt last,<br /></p>
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UnaryPredicate q <span class="br0">)</span><span class="sy4">;</span></div>
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</td>
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<td class="t-dcl-nopad"></td>
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<td><span class="t-mark-rev t-since-cxx11">(C++11 起)</span><br />
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<span class="t-mark-rev t-until-cxx20">(C++20 前)</span></td>
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</tr>
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<tr class="t-dcl t-since-cxx20">
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<td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> <span class="kw1">class</span> InputIt, <span class="kw1">class</span> UnaryPredicate <span class="sy1">></span><br /></span>
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<p><span class="kw4">constexpr</span> InputIt find_if_not<span class="br0">(</span> InputIt first, InputIt last,<br /></p>
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UnaryPredicate q <span class="br0">)</span><span class="sy4">;</span></div>
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</td>
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<td class="t-dcl-nopad"></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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</tbody>
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<tbody>
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<tr class="t-dcl t-since-cxx17">
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<td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> <span class="kw1">class</span> ExecutionPolicy, <span class="kw1">class</span> ForwardIt, <span class="kw1">class</span> UnaryPredicate <span class="sy1">></span><br /></span>
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<p>ForwardIt find_if_not<span class="br0">(</span> ExecutionPolicy<span class="sy3">&&</span> policy, ForwardIt first, ForwardIt last,<br /></p>
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UnaryPredicate q <span class="br0">)</span><span class="sy4">;</span></div>
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</td>
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<td>(6)</td>
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<td><span class="t-mark-rev t-since-cxx17">(C++17 起)</span></td>
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</tr>
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<tr class="t-dcl-sep">
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<td></td>
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<td></td>
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<td></td>
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</tr>
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</tbody>
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</table>
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<p>返回指向范围 <code>[first, last)</code> 中满足特定判别标准的首个元素的迭代器：</p>
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<div class="t-li1"><span class="t-li">1)</span> <code>find</code> 搜索等于 <code>value</code> 的元素。</div>
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<div class="t-li1"><span class="t-li">3)</span> <code>find_if</code> 搜索谓词 <code>p</code> 对其返回 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">true</span></span></span> 的元素。</div>
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<div class="t-li1"><span class="t-li">5)</span> <code>find_if_not</code> 搜索谓词 <code>q</code> 对其返回 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">false</span></span></span> 的元素。</div>
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<div class="t-li1"><span class="t-li">2,4,6)</span> 同 <span class="t-v">(1,3,5)</span> ，但按照 <code>policy</code> 执行。这些重载仅若 <span class="t-rev-inl t-until-cxx20"><span><span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-algorithm-is_execution_policy.html"><span class="kw1564">std::<span class="me2">is_execution_policy_v</span></span></a><span class="sy1"><</span><a href="cpp-types-decay.html"><span class="kw629">std::<span class="me2">decay_t</span></span></a><span class="sy1"><</span>ExecutionPolicy<span class="sy1">>></span></span></span></span> <span><span class="t-mark-rev t-until-cxx20">(C++20 前)</span></span></span><span class="t-rev-inl t-since-cxx20"><span><span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-algorithm-is_execution_policy.html"><span class="kw1564">std::<span class="me2">is_execution_policy_v</span></span></a><span class="sy1"><</span>std<span class="sy4">::</span><span class="me2">remove_cvref_t</span><span class="sy1"><</span>ExecutionPolicy<span class="sy1">>></span></span></span></span> <span><span class="t-mark-rev t-since-cxx20">(C++20 起)</span></span></span> 为 true 才参与重载决议。</div>
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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>first, last</td>
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<td>-</td>
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<td>要检验的元素范围</td>
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</tr>
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<tr class="t-par">
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<td>value</td>
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<td>-</td>
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<td>要与元素比较的值</td>
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</tr>
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<tr class="t-par">
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<td>policy</td>
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<td>-</td>
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<td>所用的执行策略。细节见<a href="cpp-algorithm-execution_policy_tag_t.html">执行策略</a>。</td>
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</tr>
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<tr class="t-par">
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<td>p</td>
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<td>-</td>
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<td>若为要求的元素则返回 ​<span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">true</span></span></span> 的一元谓词。<br />
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<p>对每个（可为 const 的） <code>VT</code> 类型参数 <code>v</code> ，其中 <code>VT</code> 是 <code>InputIt</code> 的值类型，表达式 <span class="t-c"><span class="mw-geshi cpp source-cpp">p<span class="br0">(</span>v<span class="br0">)</span></span></span> 必须可转换为 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span></span></span> ，无关乎<a href="cpp-language-value_category.html">值类别</a>，而且必须不修改 <code>v</code> 。从而不允许 <span class="t-c"><span class="mw-geshi cpp source-cpp">VT<span class="sy3">&</span></span></span> 类型参数<span class="t-rev-inl t-since-cxx11"><span>，亦不允许 <span class="t-c"><span class="mw-geshi cpp source-cpp">VT</span></span> ，除非对 <code>VT</code> 而言移动等价于复制</span> <span><span class="t-mark-rev t-since-cxx11">(C++11 起)</span></span></span>。 ​</p>
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</td>
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</tr>
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<tr class="t-par">
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<td>q</td>
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<td>-</td>
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<td>若为要求的元素则返回 ​<span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">false</span></span></span> 的一元谓词。<br />
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<p>对每个（可为 const 的） <code>VT</code> 类型参数 <code>v</code> ，其中 <code>VT</code> 是 <code>InputIt</code> 的值类型，表达式 <span class="t-c"><span class="mw-geshi cpp source-cpp">q<span class="br0">(</span>v<span class="br0">)</span></span></span> 必须可转换为 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span></span></span> ，无关乎<a href="cpp-language-value_category.html">值类别</a>，而且必须不修改 <code>v</code> 。从而不允许 <span class="t-c"><span class="mw-geshi cpp source-cpp">VT<span class="sy3">&</span></span></span> 类型参数<span class="t-rev-inl t-since-cxx11"><span>，亦不允许 <span class="t-c"><span class="mw-geshi cpp source-cpp">VT</span></span> ，除非对 <code>VT</code> 而言移动等价于复制</span> <span><span class="t-mark-rev t-since-cxx11">(C++11 起)</span></span></span>。 ​</p>
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</td>
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</tr>
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<tr class="t-par-hitem">
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<td colspan="3">类型要求</td>
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</tr>
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<tr class="t-par-req">
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<td colspan="3">-
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<div class="spacer"></div>
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<code>InputIt</code> 必须满足<a href="cpp-named_req-InputIterator.html"><span style="font-style:italic">老式输入迭代器</span> <span style="font-family: Georgia, 'DejaVu Serif', serif; font-style:italic">(LegacyInputIterator)</span></a> 的要求。</td>
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</tr>
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<tr class="t-par-req">
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<td colspan="3">-
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<div class="spacer"></div>
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<code>ForwardIt</code> 必须满足<a href="cpp-named_req-ForwardIterator.html"><span style="font-style:italic">老式向前迭代器</span> <span style="font-family: Georgia, 'DejaVu Serif', serif; font-style:italic">(LegacyForwardIterator)</span></a> 的要求。</td>
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</tr>
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<tr class="t-par-req">
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<td colspan="3">-
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<div class="spacer"></div>
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<code>UnaryPredicate</code> 必须满足<a href="cpp-named_req-Predicate.html"><span style="font-style:italic">谓词</span> <span style="font-family: Georgia, 'DejaVu Serif', serif; font-style:italic">(Predicate)</span></a> 的要求。</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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<p>指向首个满足条件的迭代器，或若找不到这种元素则为 <code>last</code> 。</p>
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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 <code>last</code> - <code>first</code> 次谓词。</p>
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<h3><span class="mw-headline" id=".E5.BC.82.E5.B8.B8">异常</span></h3>
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<p>拥有名为 <code>ExecutionPolicy</code> 的模板形参的重载按下列方式报告错误：</p>
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<ul>
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<li>若作为算法一部分调用的函数的执行抛出异常，且 <code>ExecutionPolicy</code> 为<a href="cpp-algorithm-execution_policy_tag_t.html">标准策略</a>之一，则调用 <span class="t-lc"><a href="cpp-error-terminate.html">std::terminate</a></span> 。对于任何其他 <code>ExecutionPolicy</code> ，行为是实现定义的。</li>
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<li>若算法无法分配内存，则抛出 <span class="t-lc"><a href="cpp-memory-new-bad_alloc.html">std::bad_alloc</a></span> 。</li>
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</ul>
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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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<th>版本一</th>
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</tr>
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<tr>
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<td>
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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">template</span><span class="sy1"><</span><span class="kw1">class</span> InputIt, <span class="kw1">class</span> T<span class="sy1">></span>
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InputIt find<span class="br0">(</span>InputIt first, InputIt last, <span class="kw4">const</span> T<span class="sy3">&</span> value<span class="br0">)</span>
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<span class="br0">{</span>
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<span class="kw1">for</span> <span class="br0">(</span><span class="sy4">;</span> first <span class="sy3">!</span><span class="sy1">=</span> last<span class="sy4">;</span> <span class="sy2">++</span>first<span class="br0">)</span> <span class="br0">{</span>
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<span class="kw1">if</span> <span class="br0">(</span><span class="sy2">*</span>first <span class="sy1">==</span> value<span class="br0">)</span> <span class="br0">{</span>
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<span class="kw1">return</span> first<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">return</span> last<span class="sy4">;</span>
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<span class="br0">}</span></pre></div>
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</div>
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</td>
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</tr>
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<tr>
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<th>版本二</th>
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</tr>
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<tr>
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<td>
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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">template</span><span class="sy1"><</span><span class="kw1">class</span> InputIt, <span class="kw1">class</span> UnaryPredicate<span class="sy1">></span>
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InputIt find_if<span class="br0">(</span>InputIt first, InputIt last, UnaryPredicate p<span class="br0">)</span>
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<span class="br0">{</span>
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<span class="kw1">for</span> <span class="br0">(</span><span class="sy4">;</span> first <span class="sy3">!</span><span class="sy1">=</span> last<span class="sy4">;</span> <span class="sy2">++</span>first<span class="br0">)</span> <span class="br0">{</span>
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<span class="kw1">if</span> <span class="br0">(</span>p<span class="br0">(</span><span class="sy2">*</span>first<span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span>
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<span class="kw1">return</span> first<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">return</span> last<span class="sy4">;</span>
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<span class="br0">}</span></pre></div>
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</div>
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</td>
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</tr>
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<tr>
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<th>版本三</th>
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</tr>
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<tr>
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<td>
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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">template</span><span class="sy1"><</span><span class="kw1">class</span> InputIt, <span class="kw1">class</span> UnaryPredicate<span class="sy1">></span>
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InputIt find_if_not<span class="br0">(</span>InputIt first, InputIt last, UnaryPredicate q<span class="br0">)</span>
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<span class="br0">{</span>
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<span class="kw1">for</span> <span class="br0">(</span><span class="sy4">;</span> first <span class="sy3">!</span><span class="sy1">=</span> last<span class="sy4">;</span> <span class="sy2">++</span>first<span class="br0">)</span> <span class="br0">{</span>
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<span class="kw1">if</span> <span class="br0">(</span><span class="sy3">!</span>q<span class="br0">(</span><span class="sy2">*</span>first<span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span>
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<span class="kw1">return</span> first<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">return</span> last<span class="sy4">;</span>
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<span class="br0">}</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=".E6.B3.A8.E8.A7.A3">注解</span></h3>
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<p>若你没有 C++11 ，则 <code>std::find_if_not</code> 的等价版本是以取反的谓词使用 <code>std::find_if</code> 。</p>
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<table class="eq-fun-cpp-table">
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<tr>
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<td>
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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">template</span><span class="sy1"><</span><span class="kw1">class</span> InputIt, <span class="kw1">class</span> UnaryPredicate<span class="sy1">></span>
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InputIt find_if_not<span class="br0">(</span>InputIt first, InputIt last, UnaryPredicate q<span class="br0">)</span>
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<span class="br0">{</span>
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<span class="kw1">return</span> std<span class="sy4">::</span><span class="me2">find_if</span><span class="br0">(</span>first, last, <a href="cpp-utility-functional-not1.html"><span class="kw1050">std::<span class="me2">not1</span></span></a><span class="br0">(</span>q<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="br0">}</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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|
<p>以下示例在给定的 <span class="t-lc"><a href="cpp-container-vector.html">std::vector</a></span> 中查找整数。</p>
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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 <iostream></span>
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<span class="co2">#include <algorithm></span>
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<span class="co2">#include <vector></span>
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<span class="co2">#include <iterator></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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<a href="cpp-container-vector.html"><span class="kw1269">std::<span class="me2">vector</span></span></a><span class="sy1"><</span><span class="kw4">int</span><span class="sy1">></span> v<span class="br0">{</span><span class="nu0">1</span>, <span class="nu0">2</span>, <span class="nu0">3</span>, <span class="nu0">4</span><span class="br0">}</span><span class="sy4">;</span>
|
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<span class="kw4">int</span> n1 <span class="sy1">=</span> <span class="nu0">3</span><span class="sy4">;</span>
|
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<span class="kw4">int</span> n2 <span class="sy1">=</span> <span class="nu0">5</span><span class="sy4">;</span>
|
|
<span class="kw4">auto</span> is_even <span class="sy1">=</span> <span class="br0">[</span><span class="br0">]</span><span class="br0">(</span><span class="kw4">int</span> i<span class="br0">)</span><span class="br0">{</span> <span class="kw1">return</span> i<span class="sy2">%</span><span class="nu19">2</span> <span class="sy1">==</span> <span class="nu0">0</span><span class="sy4">;</span> <span class="br0">}</span><span class="sy4">;</span>
|
|
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|
<span class="kw4">auto</span> result1 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">find</span><span class="br0">(</span>begin<span class="br0">(</span>v<span class="br0">)</span>, end<span class="br0">(</span>v<span class="br0">)</span>, n1<span class="br0">)</span><span class="sy4">;</span>
|
|
<span class="kw4">auto</span> result2 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">find</span><span class="br0">(</span>begin<span class="br0">(</span>v<span class="br0">)</span>, end<span class="br0">(</span>v<span class="br0">)</span>, n2<span class="br0">)</span><span class="sy4">;</span>
|
|
<span class="kw4">auto</span> result3 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">find_if</span><span class="br0">(</span>begin<span class="br0">(</span>v<span class="br0">)</span>, end<span class="br0">(</span>v<span class="br0">)</span>, is_even<span class="br0">)</span><span class="sy4">;</span>
|
|
|
|
<span class="br0">(</span>result1 <span class="sy3">!</span><span class="sy1">=</span> <a href="cpp-iterator-end.html"><span class="kw680">std::<span class="me2">end</span></span></a><span class="br0">(</span>v<span class="br0">)</span><span class="br0">)</span>
|
|
<span class="sy4">?</span> <a href="cpp-io-cout.html"><span class="kw1755">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"v contains "</span> <span class="sy1"><<</span> n1 <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span>
|
|
<span class="sy4">:</span> <a href="cpp-io-cout.html"><span class="kw1755">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"v does not contain "</span> <span class="sy1"><<</span> n1 <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
|
|
|
|
<span class="br0">(</span>result2 <span class="sy3">!</span><span class="sy1">=</span> <a href="cpp-iterator-end.html"><span class="kw680">std::<span class="me2">end</span></span></a><span class="br0">(</span>v<span class="br0">)</span><span class="br0">)</span>
|
|
<span class="sy4">?</span> <a href="cpp-io-cout.html"><span class="kw1755">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"v contains "</span> <span class="sy1"><<</span> n2 <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span>
|
|
<span class="sy4">:</span> <a href="cpp-io-cout.html"><span class="kw1755">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"v does not contain "</span> <span class="sy1"><<</span> n2 <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
|
|
|
|
<span class="br0">(</span>result3 <span class="sy3">!</span><span class="sy1">=</span> <a href="cpp-iterator-end.html"><span class="kw680">std::<span class="me2">end</span></span></a><span class="br0">(</span>v<span class="br0">)</span><span class="br0">)</span>
|
|
<span class="sy4">?</span> <a href="cpp-io-cout.html"><span class="kw1755">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"v contains an even number: "</span> <span class="sy1"><<</span> <span class="sy2">*</span>result3 <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span>
|
|
<span class="sy4">:</span> <a href="cpp-io-cout.html"><span class="kw1755">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"v does not contain even numbers<span class="es1">\n</span>"</span><span class="sy4">;</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">v contains 3
|
|
v does not contain 5
|
|
v contains an even number: 2</pre></div>
|
|
</div>
|
|
</div>
|
|
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
|
|
<table class="t-dsc-begin">
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-adjacent_find.html"><span class="t-lines"><span>adjacent_find</span></span></a></div>
|
|
</div>
|
|
</td>
|
|
<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">(函数模板)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<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>
|
|
</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-find_first_of.html"><span class="t-lines"><span>find_first_of</span></span></a></div>
|
|
</div>
|
|
</td>
|
|
<td>搜索元素集合中的任意元素<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-mismatch.html"><span class="t-lines"><span>mismatch</span></span></a></div>
|
|
</div>
|
|
</td>
|
|
<td>寻找两个范围出现不同的首个位置<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-search.html"><span class="t-lines"><span>search</span></span></a></div>
|
|
</div>
|
|
</td>
|
|
<td>搜索一个元素范围<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-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>
|
|
</td>
|
|
<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>
|
|
</table>
|
|
</div>
|
|
<div class="visualClear"></div>
|
|
</div>
|
|
</div>
|
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</div>
|
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</body>
|
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</html>
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