237 lines
15 KiB
HTML
237 lines
15 KiB
HTML
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<title>std::common_iterator</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_iterator_common_iterator 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>common_iterator</h1>
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<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-iterator.html">iterator</a></span></div>
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<div>定义于头文件 <code><a href="cpp-header-iterator.html"><iterator></a></code></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">input_or_output_iterator</span> I, std<span class="sy4">::</span><span class="me2">sentinel_for</span><span class="sy1"><</span>I<span class="sy1">></span> S <span class="sy1">></span><br /></span>
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<p> requires <span class="br0">(</span> <span class="sy3">!</span>std<span class="sy4">::</span><span class="me2">same_as</span><span class="sy1"><</span>I, S<span class="sy1">></span> <span class="sy3">&&</span> std<span class="sy4">::</span><span class="me2">copyable</span><span class="sy1"><</span>I<span class="sy1">></span> <span class="br0">)</span><br /></p>
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<span class="kw1">class</span> common_iterator<span class="sy4">;</span></div>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span></td>
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<p><code>std::common_iterator</code> 是含有迭代器或哨位之一并定义适合的比较运算符 <span class="t-c"><span class="mw-geshi cpp source-cpp">operator<span class="sy1">==</span></span></span> ，从而可以将非共用范围（其中 <code>I</code> 与 <code>S</code> 有别）表示成 <a href="cpp-ranges-common_range.html"><code>common_range</code></a> 的迭代器 <code>I</code> / 哨位 <code>S</code> 适配器。<br />
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能以 <code>std::common_iterator</code> 为迭代器/哨位对所表示的序列与期待 <a href="cpp-ranges-common_range.html"><code>common_range</code></a> 式序列的遗留函数间的“桥梁”。</p>
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<h3><span class="mw-headline" id=".E6.88.90.E5.91.98.E5.87.BD.E6.95.B0">成员函数</span></h3>
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<div class="t-dsc-member-div t-dsc-member-nobold-div">
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<div><a href="cpp-iterator-common_iterator-common_iterator.html"><span class="t-lines"><span>(构造函数)</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</td>
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<td>构造新的迭代器适配器<br />
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<span class="t-mark">(公开成员函数)</span></td>
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<div><a href="cpp-iterator-common_iterator-operator=.html"><span class="t-lines"><span>operator=</span></span></a></div>
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<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>赋值另一迭代器适配器<br />
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<span class="t-mark">(公开成员函数)</span></td>
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<div><a href="cpp-iterator-common_iterator-operator*.html"><span class="t-lines"><span>operator*</span><span>operator-></span></span></a></div>
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<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>访问被指向的元素<br />
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<span class="t-mark">(公开成员函数)</span></td>
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<div><a href="cpp-iterator-common_iterator-operator_arith.html"><span class="t-lines"><span>operator++</span><span>operator++<span class="t-dsc-small">(int)</span></span></span></a></div>
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<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>推进迭代器适配器<br />
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<span class="t-mark">(公开成员函数)</span></td>
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<h3><span class="mw-headline" id=".E6.88.90.E5.91.98.E5.AF.B9.E8.B1.A1">成员对象</span></h3>
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<td>成员名</td>
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<td>定义</td>
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<td><code><i>var</i></code> <span class="t-mark">(私有)</span></td>
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<td><span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-utility-variant.html"><span class="kw1085">std::<span class="me2">variant</span></span></a><span class="sy1"><</span>I, S<span class="sy1">></span></span></span> 类型对象，名字仅用于阐释</td>
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<h3><span class="mw-headline" id=".E9.9D.9E.E6.88.90.E5.91.98.E5.87.BD.E6.95.B0">非成员函数</span></h3>
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<div><a href="cpp-iterator-common_iterator-operator_cmp.html"><span class="t-lines"><span>operator==</span></span></a></div>
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<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>比较底层迭代器或哨位<br />
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<span class="t-mark">(函数模板)</span></td>
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<div><a href="cpp-iterator-common_iterator-operator-.html"><span class="t-lines"><span>operator-</span></span></a></div>
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<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>计算二个迭代器适配器间的距离<br />
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<span class="t-mark">(函数模板)</span></td>
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<tr class="t-dsc">
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<div class="t-dsc-member-div">
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<div><a href="cpp-iterator-common_iterator-iter_move.html"><span class="t-lines"><span>iter_move</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</td>
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<td>转型解引用底层迭代器的结果为其所关联的右值引用类型<br />
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<span class="t-mark">(函数)</span></td>
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<div class="t-dsc-member-div">
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<div><a href="cpp-iterator-common_iterator-iter_swap.html"><span class="t-lines"><span>iter_swap</span></span></a></div>
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<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>交换二个底层迭代器所指向的对象<br />
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<span class="t-mark">(函数模板)</span></td>
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<h3><span class="mw-headline" id=".E8.BE.85.E5.8A.A9.E7.B1.BB">辅助类</span></h3>
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<div><a href="cpp-iterator-common_iterator-incrementable_traits.html"><span class="t-lines"><span>std::incrementable_traits<span class="t-dsc-small"><std::common_iterator></span></span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</td>
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<td>计算 <span class="t-lc">std::common_iterator</span> 类型的关联差类型<br />
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<span class="t-mark">(类模板特化)</span></td>
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<div class="t-dsc-member-div">
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<div><a href="cpp-iterator-common_iterator-iterator_traits.html"><span class="t-lines"><span>std::iterator_traits<span class="t-dsc-small"><std::common_iterator></span></span></span></a></div>
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<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>对 <span class="t-lc">std::counted_iterator</span> 类型的属性提供均一的接口<br />
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<span class="t-mark">(类模板特化)</span></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="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 <list></span>
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<span class="co2">#include <iostream></span>
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<span class="co2">#include <iterator></span>
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<span class="co2">#include <string></span>
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<span class="kw1">template</span> <span class="sy1"><</span><span class="kw1">class</span> ForwardIter<span class="sy1">></span>
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<span class="kw4">void</span> fire<span class="br0">(</span>ForwardIter first, ForwardIter last<span class="br0">)</span> <span class="br0">{</span>
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<a href="cpp-algorithm-copy.html"><span class="kw1582">std::<span class="me2">copy</span></span></a><span class="br0">(</span>first, last, <a href="cpp-iterator-ostream_iterator.html"><span class="kw670">std::<span class="me2">ostream_iterator</span></span></a><span class="sy1"><</span><a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a><span class="sy1">></span><span class="br0">{</span><a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a>, <span class="st0">" "</span><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="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
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<a href="cpp-container-list.html"><span class="kw1275">std::<span class="me2">list</span></span></a><span class="sy1"><</span><a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a><span class="sy1">></span> stars<span class="br0">{</span><span class="st0">"Pollux"</span>, <span class="st0">"Arcturus"</span>, <span class="st0">"Mira"</span>, <span class="st0">"Aldebaran"</span>, <span class="st0">"Sun"</span><span class="br0">}</span><span class="sy4">;</span>
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<span class="kw1">using</span> IT <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">common_iterator</span><span class="sy1"><</span>
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std<span class="sy4">::</span><span class="me2">counted_iterator</span><span class="sy1"><</span><a href="cpp-container-list.html"><span class="kw1275">std::<span class="me2">list</span></span></a><span class="sy1"><</span><a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a><span class="sy1">></span><span class="sy4">::</span><span class="me2">iterator</span><span class="sy1">></span>,
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std<span class="sy4">::</span><span class="me2">default_sentinel_t</span><span class="sy1">></span><span class="sy4">;</span>
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fire<span class="br0">(</span> IT<span class="br0">(</span>std<span class="sy4">::</span><span class="me2">counted_iterator</span><span class="br0">(</span>stars.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span>, stars.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span><span class="sy2">-</span><span class="nu0">1</span><span class="br0">)</span><span class="br0">)</span>,
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IT<span class="br0">(</span>std<span class="sy4">::</span><span class="me2">default_sentinel</span><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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<p>输出：</p>
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<div dir="ltr" class="mw-geshi" style="text-align: left;">
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<div class="text source-text">
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<pre class="de1">Pollux Arcturus Mira Aldebaran</pre></div>
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</div>
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</div>
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<h3><span class="mw-headline" id=".E5.BC.95.E7.94.A8">引用</span></h3>
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<div class="t-ref-std-c++20">
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<ul>
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<li>C++20 标准（ISO/IEC 14882:2020）：</li>
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</ul>
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<dl>
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<dd>
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<ul>
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<li>23.5.4 Common iterators [iterators.common]</li>
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</ul>
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</dd>
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</dl>
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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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<div class="t-dsc-member-div">
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<div><a href="cpp-ranges-common_range.html"><span class="t-lines"><span>ranges::common_range</span></span></a></div>
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<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>指定范围拥有相同的迭代器和哨位类型<br />
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<span class="t-mark">(概念)</span></td>
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</tr>
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<tr class="t-dsc">
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<div class="t-dsc-member-div">
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<div><a href="cpp-ranges-common_view.html"><span class="t-lines"><span>ranges::common_view</span><span>views::common</span></span></a></div>
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<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>转换 <a href="cpp-ranges-view.html"><code>view</code></a> 为 <a href="cpp-ranges-common_range.html"><code>common_range</code></a><br />
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<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
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</tr>
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</table>
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</div>
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<div class="visualClear"></div>
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