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<title>std::ranges::common_view&lt;V&gt;::size</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>size</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> size<span class="br0">(</span><span class="br0">)</span> requires ranges<span class="sy4">::</span><span class="me2">sized_range</span><span class="sy1">&lt;</span>V<span class="sy1">&gt;</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> size<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires ranges<span class="sy4">::</span><span class="me2">sized_range</span><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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<p>&#36820;&#22238;&#20803;&#32032;&#25968;&#12290;</p>
<p>&#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="br0">{</span> <span class="kw1">return</span> ranges<span class="sy4">::</span><span class="me2">size</span><span class="br0">(</span>base_<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span></span></span> &#65292;&#20854;&#20013; <code><i>base_</i></code> &#20026;&#24213;&#23618;&#35270;&#22270;&#12290;</p>
<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>&#20803;&#32032;&#25968;&#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;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">static</span> <span class="kw4">auto</span> v1 <span class="sy1">=</span> <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="nu0">5</span><span class="br0">}</span><span class="sy4">;</span>
<span class="kw4">constexpr</span> <span class="kw4">auto</span> common1 <span class="br0">{</span> v1 <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="br0">}</span><span class="sy4">;</span>
static_assert<span class="br0">(</span>common1.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">==</span> <span class="nu0">5</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw4">constexpr</span> <span class="kw4">auto</span> take3 <span class="br0">{</span> v1 <span class="sy3">|</span> std<span class="sy4">::</span><span class="me2">views</span><span class="sy4">::</span><span class="me2">reverse</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="br0">}</span><span class="sy4">;</span>
<span class="kw4">constexpr</span> <span class="kw4">auto</span> common2 <span class="br0">{</span> take3 <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="br0">}</span><span class="sy4">;</span>
static_assert<span class="br0">(</span>common2.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">==</span> <span class="nu0">3</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw1">using</span> <span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">literals</span><span class="sy4">;</span>
<span class="kw4">constexpr</span> <span class="kw4">static</span> <span class="kw4">auto</span> v2 <span class="sy1">=</span> <span class="br0">{</span> <span class="st0">&quot;&and;&quot;</span>sv, <span class="st0">&quot;&or;&quot;</span>sv, <span class="st0">&quot;&exist;&quot;</span>sv, <span class="st0">&quot;&forall;&quot;</span>sv <span class="br0">}</span><span class="sy4">;</span>
static_assert<span class="br0">(</span>std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">views</span><span class="sy4">::</span><span class="me2">common</span><span class="br0">(</span>v2<span class="br0">)</span>.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">==</span> <span class="nu0">4</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span></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-size.html"><span class="t-lines"><span>ranges::size</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;&#31561;&#20110;&#33539;&#22260;&#22823;&#23567;&#30340;&#25972;&#25968;<br />
<span class="t-mark">(&#23450;&#21046;&#28857;&#23545;&#35937;)</span></td>
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<div><a href="cpp-ranges-ssize.html"><span class="t-lines"><span>ranges::ssize</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;&#31561;&#20110;&#33539;&#22260;&#22823;&#23567;&#30340;&#26377;&#31526;&#21495;&#25972;&#25968;<br />
<span class="t-mark">(&#23450;&#21046;&#28857;&#23545;&#35937;)</span></td>
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