76 lines
5.1 KiB
HTML
76 lines
5.1 KiB
HTML
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<title>std::basic_ostream<CharT,Traits>::swap</title>
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::basic_ostream<CharT,Traits>::</span>swap</h1>
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<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-io.html">io</a>‎ | <a href="cpp-io-basic_ostream.html">basic ostream</a></span></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">protected</span><span class="sy4">:</span><br />
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<span class="kw4">void</span> swap<span class="br0">(</span>basic_ostream<span class="sy3">&</span> rhs<span class="br0">)</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-since-cxx11">(C++11 起)</span></td>
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<p>调用 <span class="t-c"><span class="mw-geshi cpp source-cpp">basic_ios<span class="sy4">::</span><span class="me2">swap</span><span class="br0">(</span>rhs<span class="br0">)</span></span></span> 交换 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this</span></span> 和 <code>rhs</code> 间的基类数据成员，除了 <span class="t-c"><span class="mw-geshi cpp source-cpp">rdbuf<span class="br0">(</span><span class="br0">)</span></span></span> 。此 swap 函数受保护：它为可交换输出流类 <span class="t-lc"><a href="cpp-io-basic_ofstream.html">std::basic_ofstream</a></span> 和 <span class="t-lc"><a href="cpp-io-basic_ostringstream.html">std::basic_ostringstream</a></span> 的 swap 函数所调用，这些函数知晓如何正确交换关联的流缓冲。</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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<td>rhs</td>
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<td>-</td>
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<td>要与之交换的同类型 basic_ostream</td>
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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="cpp source-cpp">
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<pre class="de1"><span class="co2">#include <sstream></span>
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<span class="co2">#include <iostream></span>
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<span class="co2">#include <utility></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-io-basic_ostringstream.html"><span class="kw1736">std::<span class="me2">ostringstream</span></span></a> s1<span class="br0">(</span><span class="st0">"hello"</span><span class="br0">)</span><span class="sy4">;</span>
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<a href="cpp-io-basic_ostringstream.html"><span class="kw1736">std::<span class="me2">ostringstream</span></span></a> s2<span class="br0">(</span><span class="st0">"bye"</span><span class="br0">)</span><span class="sy4">;</span>
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s1.<span class="me1">swap</span><span class="br0">(</span>s2<span class="br0">)</span><span class="sy4">;</span> <span class="co1">// OK ： ostringstream 拥有公开 swap()</span>
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<a href="cpp-algorithm-swap.html"><span class="kw1599">std::<span class="me2">swap</span></span></a><span class="br0">(</span>s1, s2<span class="br0">)</span><span class="sy4">;</span> <span class="co1">// OK ：调用 s1.swap(s2)</span>
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<span class="co1">// std::cout.swap(s2); // 错误： swap 是受保护成员</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> s1.<span class="me1">str</span><span class="br0">(</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></pre></div>
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<p>输出：</p>
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<div class="text source-text">
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<pre class="de1">hello</pre></div>
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