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<title>std::ranges::common_view&lt;V&gt;::begin</title>
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::ranges::common_view&lt;V&gt;::</span>begin</h1>
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<div id="contentSub"><span class="subpages">&lt; <a href="cpp.html">cpp</a>&lrm; | <a href="cpp-ranges.html">ranges</a>&lrm; | <a href="cpp-ranges-common_view.html">common view</a></span></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span></span></div>
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<td>(1)</td>
<td><span class="t-mark-rev t-since-cxx20">(C++20 &#36215;)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires range<span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span><span class="sy4">;</span></span></div>
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<td>(2)</td>
<td><span class="t-mark-rev t-since-cxx20">(C++20 &#36215;)</span></td>
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<div class="t-li1"><span class="t-li">1)</span> &#36820;&#22238;&#25351;&#21521; <code>common_view</code> &#39318;&#20803;&#32032;&#30340;&#36845;&#20195;&#22120;&#65292;&#21363;&#65306;
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<li><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>base_<span class="br0">)</span></span></span> &#65292;&#33509; <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">random_access_range</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span></span></span> &#19982; <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">sized_range</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span></span></span> &#22343;&#24471;&#21040;&#28385;&#36275;&#65292;</li>
<li>&#21542;&#21017;&#20026; <span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">common_iterator</span><span class="sy1">&lt;</span>ranges<span class="sy4">::</span><span class="me2">iterator_t</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</span>, ranges<span class="sy4">::</span><span class="me2">sentinel_t</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;&gt;</span><span class="br0">(</span>ranges<span class="sy4">::</span><span class="me2">begin</span><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span></span></span> &#12290;</li>
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&#27492;&#22788; <code><i>base_</i></code> &#65288;&#21517;&#31216;&#20165;&#29992;&#20110;&#38416;&#37322;&#30446;&#30340;&#65289;&#20026;&#24213;&#23618;&#35270;&#22270;&#12290;</div>
<div class="t-li1"><span class="t-li">2)</span> &#21516; <span class="t-v">(1)</span> &#65292;&#20294; <code>V</code> &#20026; const &#38480;&#23450;&#12290;</div>
<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">&#21442;&#25968;</span></h3>
<p>&#65288;&#26080;&#65289;</p>
<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">&#36820;&#22238;&#20540;</span></h3>
<p>&#25351;&#21521;&#24213;&#23618;&#35270;&#22270;&#36215;&#22987;&#30340;&#36845;&#20195;&#22120;&#12290;</p>
<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;iostream&gt;</span>
<span class="co2">#include &lt;numeric&gt;</span>
<span class="co2">#include &lt;ranges&gt;</span>
<span class="co2">#include &lt;string_view&gt;</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
<span class="kw4">constexpr</span> <span class="kw4">auto</span> common <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">views</span><span class="sy4">::</span><span class="me2">iota</span><span class="br0">(</span><span class="nu0">1</span><span class="br0">)</span>
<span class="sy3">|</span> std<span class="sy4">::</span><span class="me2">views</span><span class="sy4">::</span><span class="me2">take</span><span class="br0">(</span><span class="nu0">3</span><span class="br0">)</span>
<span class="sy3">|</span> std<span class="sy4">::</span><span class="me2">views</span><span class="sy4">::</span><span class="me2">common</span>
<span class="sy4">;</span>
<span class="kw1">for</span> <span class="br0">(</span><span class="kw4">int</span> i<span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span> <span class="kw4">int</span> e <span class="sy4">:</span> common<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">&lt;&lt;</span> <span class="br0">(</span>i<span class="sy2">++</span> <span class="sy4">?</span> <span class="st0">&quot; + &quot;</span> <span class="sy4">:</span> <span class="st0">&quot;&quot;</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> e<span class="sy4">;</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">&lt;&lt;</span> <span class="st0">&quot; = &quot;</span> <span class="sy1">&lt;&lt;</span> <a href="cpp-algorithm-accumulate.html"><span class="kw1651">std::<span class="me2">accumulate</span></span></a><span class="br0">(</span>common.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span>, common.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span>, <span class="nu0">0</span><span class="br0">)</span> <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">1 + 2 + 3 = 6</pre></div>
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<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">&#21442;&#38405;</span></h3>
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<div><a href="cpp-ranges-common_view-end.html"><span class="t-lines"><span>end</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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<td>&#36820;&#22238;&#25351;&#21521;&#26411;&#23614;&#30340;&#36845;&#20195;&#22120;<br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
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<div><a href="cpp-ranges-begin.html"><span class="t-lines"><span>ranges::begin</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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<td>&#36820;&#22238;&#25351;&#21521;&#33539;&#22260;&#36215;&#22987;&#30340;&#36845;&#20195;&#22120;<br />
<span class="t-mark">(&#23450;&#21046;&#28857;&#23545;&#35937;)</span></td>
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<div><a href="cpp-ranges-end.html"><span class="t-lines"><span>ranges::end</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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<td>&#36820;&#22238;&#25351;&#31034;&#33539;&#22260;&#32467;&#23614;&#30340;&#21736;&#20301;<br />
<span class="t-mark">(&#23450;&#21046;&#28857;&#23545;&#35937;)</span></td>
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