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<title>std::basic_string&lt;CharT,Traits,Allocator&gt;::swap</title>
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::basic_string&lt;CharT,Traits,Allocator&gt;::</span>swap</h1>
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<div id="contentSub"><span class="subpages">&lt; <a href="cpp.html">cpp</a>&lrm; | <a href="cpp-string.html">string</a>&lrm; | <a href="cpp-string-basic_string.html">basic string</a></span></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">void</span> swap<span class="br0">(</span> basic_string<span class="sy3">&amp;</span> other <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-until-cxx17">(C++17 &#21069;)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">void</span> swap<span class="br0">(</span> basic_string<span class="sy3">&amp;</span> other <span class="br0">)</span> <span class="kw1">noexcept</span><span class="br0">(</span><span class="coMULTI">/* see below */</span><span class="br0">)</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-since-cxx17">(C++17 &#36215;)</span><br />
<span class="t-mark-rev t-until-cxx20">(C++20 &#21069;)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> <span class="kw4">void</span> swap<span class="br0">(</span> basic_string<span class="sy3">&amp;</span> other <span class="br0">)</span> <span class="kw1">noexcept</span><span class="br0">(</span><span class="coMULTI">/* see below */</span><span class="br0">)</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 &#36215;)</span></td>
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<p>&#20132;&#25442; string &#19982; <code>other</code> &#30340;&#20869;&#23481;&#12290;&#21487;&#33021;&#38750;&#27861;&#21270;&#25152;&#26377;&#36845;&#20195;&#22120;&#21644;&#24341;&#29992;&#12290;</p>
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<p>&#33509; <code>Allocator</code> &#19981;&#22312;&#20132;&#25442;&#26102;&#20256;&#25773;&#19988; <code>*this</code> &#19982; <code>other</code> &#30340;&#20998;&#37197;&#22120;&#19981;&#30456;&#31561;&#21017;&#34892;&#20026;&#26410;&#23450;&#20041;&#12290;</p>
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<td><span class="t-mark-rev t-since-cxx11">(C++11 &#36215;)</span></td>
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<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">&#21442;&#25968;</span></h3>
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<td>other</td>
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<td>&#35201;&#19982;&#20043;&#20132;&#25442;&#20869;&#23481;&#30340; string</td>
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<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">&#36820;&#22238;&#20540;</span></h3>
<p>&#65288;&#26080;&#65289;</p>
<h3><span class="mw-headline" id=".E5.A4.8D.E6.9D.82.E5.BA.A6">&#22797;&#26434;&#24230;</span></h3>
<p>&#24120;&#25968;&#12290;</p>
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<h3><span class="mw-headline" id=".E5.BC.82.E5.B8.B8">&#24322;&#24120;</span></h3>
<div class="t-noexcept-full"><a href="cpp-language-noexcept_spec.html"><tt>noexcept</tt></a> &#35828;&#26126;&#65306;&nbsp;&nbsp;
<div class="t-noexcept-box"><span class="t-cc"><span class="mw-geshi cpp source-cpp"><span class="kw1">noexcept</span><span class="br0">(</span><a href="cpp-memory-allocator_traits.html"><span class="kw701">std::<span class="me2">allocator_traits</span></span></a><span class="sy1">&lt;</span>Allocator<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">propagate_on_container_swap</span><span class="sy4">::</span><span class="me2">value</span><br />
<span class="sy3">||</span> <a href="cpp-memory-allocator_traits.html"><span class="kw701">std::<span class="me2">allocator_traits</span></span></a><span class="sy1">&lt;</span>Allocator<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">is_always_equal</span><span class="sy4">::</span><span class="me2">value</span><span class="br0">)</span></span></span></div>
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<td><span class="t-mark-rev t-since-cxx17">(C++17 &#36215;)</span></td>
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<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">&#31034;&#20363;</span></h3>
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<pre class="de1"><span class="co2">#include &lt;string&gt;</span>
<span class="co2">#include &lt;iostream&gt;</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
<a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a> a <span class="sy1">=</span> <span class="st0">&quot;AAA&quot;</span><span class="sy4">;</span>
<a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a> b <span class="sy1">=</span> <span class="st0">&quot;BBB&quot;</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;before swap&quot;</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;a: &quot;</span> <span class="sy1">&lt;&lt;</span> a <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;b: &quot;</span> <span class="sy1">&lt;&lt;</span> b <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span>
a.<span class="me1">swap</span><span class="br0">(</span>b<span class="br0">)</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;after swap&quot;</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;a: &quot;</span> <span class="sy1">&lt;&lt;</span> a <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;b: &quot;</span> <span class="sy1">&lt;&lt;</span> b <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div>
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<p>&#36755;&#20986;&#65306;</p>
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<pre class="de1">before swap
a: AAA
b: BBB
after swap
a: BBB
b: AAA</pre></div>
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