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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::ranges::drop_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-drop_view.html">drop 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><br /></span>
<p>&nbsp; requires <span class="br0">(</span><span class="sy3">!</span><span class="br0">(</span>__SimpleView<span class="sy1">&lt;</span>V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span><br /></p>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;ranges<span class="sy4">::</span><span class="me2">random_access_range</span><span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> 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="br0">)</span><span class="br0">)</span><span class="sy4">;</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><br />
&nbsp; requires ranges<span class="sy4">::</span><span class="me2">random_access_range</span><span class="sy1">&lt;</span><span class="kw4">const</span> V<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> 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;&#25351;&#21521; <code>drop_view</code> &#30340;&#39318;&#20803;&#32032;&#30340;&#36845;&#20195;&#22120;&#65292;&#21363;&#25351;&#21521;&#24213;&#23618;&#35270;&#22270;&#31532; <i>N</i> &#20803;&#32032;&#30340;&#36845;&#20195;&#22120;&#65292;&#25110;&#33509;&#23427;&#26377;&#23569;&#20110; <i>N</i> &#21508;&#20803;&#32032;&#21017;&#20026;&#25351;&#21521;&#24213;&#23618;&#35270;&#22270;&#26411;&#23614;&#30340;&#36845;&#20195;&#22120;&#12290;</p>
<p>&#33509; <code>V</code> &#19981;&#26159; <a href="cpp-ranges-random_access_range.html"><code>random_access_range</code></a> &#25110; <a href="cpp-ranges-sized_range.html"><code>sized_range</code></a> &#65292;&#20026;&#25552;&#20379; <a href="cpp-ranges-range.html"><code>range</code></a> &#27010;&#24565;&#25152;&#35201;&#27714;&#30340;&#30340;&#22343;&#25674;&#24120;&#25968;&#26102;&#38388;&#22797;&#26434;&#24230;&#65292;&#37325;&#36733; <span class="t-v">(1)</span> &#22312; <code>drop_view</code> &#23545;&#35937;&#20869;&#32531;&#23384;&#32467;&#26524;&#20197;&#20379;&#21518;&#32487;&#35843;&#29992;&#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><span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">next</span><span class="br0">(</span>ranges<span class="sy4">::</span><span class="me2">begin</span><span class="br0">(</span>base_<span class="br0">)</span>, count_, ranges<span class="sy4">::</span><span class="me2">end</span><span class="br0">(</span>base_<span class="br0">)</span><span class="br0">)</span></span></span> &#65292;&#20854;&#20013; <code><i>base_</i></code> &#20026;&#24213;&#23618;&#35270;&#22270;&#65292;&#32780; <code><i>count_</i></code> &#20026;&#35201;&#36339;&#36807;&#30340;&#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;algorithm&gt;</span>
<span class="co2">#include &lt;array&gt;</span>
<span class="co2">#include &lt;iostream&gt;</span>
<span class="co2">#include &lt;iterator&gt;</span>
<span class="co2">#include &lt;ranges&gt;</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
<a href="cpp-container-array.html"><span class="kw1268">std::<span class="me2">array</span></span></a> hi<span class="br0">{</span> <span class="st0">&#39;H&#39;</span>,<span class="st0">&#39;e&#39;</span>,<span class="st0">&#39;l&#39;</span>,<span class="st0">&#39;l&#39;</span>,<span class="st0">&#39;o&#39;</span>,<span class="st0">&#39;,&#39;</span>,<span class="st0">&#39; &#39;</span>,<span class="st0">&#39;C&#39;</span>,<span class="st0">&#39;+&#39;</span>,<span class="st0">&#39;+&#39;</span>,<span class="st0">&#39;2&#39;</span>,<span class="st0">&#39;0&#39;</span>,<span class="st0">&#39;!&#39;</span> <span class="br0">}</span><span class="sy4">;</span>
std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">for_each</span><span class="br0">(</span>hi, <span class="br0">[</span><span class="br0">]</span><span class="br0">(</span><span class="kw4">const</span> <span class="kw4">char</span> c<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> c<span class="sy4">;</span> <span class="br0">}</span><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">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span>
<span class="kw4">const</span> <span class="kw4">auto</span> c <span class="sy1">=</span> <a href="cpp-iterator-distance.html"><span class="kw673">std::<span class="me2">distance</span></span></a><span class="br0">(</span>hi.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span>, std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">find</span><span class="br0">(</span>hi, <span class="st0">&#39;C&#39;</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw4">auto</span> cxx <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">drop_view</span><span class="br0">{</span> hi, c <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;*drop_view::begin() == &#39;&quot;</span> <span class="sy1">&lt;&lt;</span> <span class="sy2">*</span>cxx.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;&#39;<span class="es1">\n</span>&quot;</span><span class="sy4">;</span>
<span class="co1">// *cxx.begin() = &#39;c&#39;; // &#26410;&#23450;&#20041;&#65306; &#39;views&#39; &#35201;&#29992;&#20316;&#35266;&#23519;&#22120;</span>
<span class="kw1">for</span> <span class="br0">(</span><span class="kw4">char</span> c <span class="sy4">:</span> cxx<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> c<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">&#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">Hello, C++20!
*drop_view::begin() == &#39;C&#39;
C++20!</pre></div>
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<h3><span class="mw-headline" id=".E7.BC.BA.E9.99.B7.E6.8A.A5.E5.91.8A">&#32570;&#38519;&#25253;&#21578;</span></h3>
<p>&#19979;&#21015;&#26356;&#25913;&#34892;&#20026;&#30340;&#32570;&#38519;&#25253;&#21578;&#36861;&#28335;&#22320;&#24212;&#29992;&#20110;&#20197;&#21069;&#20986;&#29256;&#30340; C++ &#26631;&#20934;&#12290;</p>
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<th>DR</th>
<th>&#24212;&#29992;&#20110;</th>
<th>&#20986;&#29256;&#26102;&#30340;&#34892;&#20026;</th>
<th>&#27491;&#30830;&#34892;&#20026;</th>
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<tr>
<td><a rel="nofollow" class="external text" href="https://cplusplus.github.io/LWG/issue3482">LWG 3482</a></td>
<td>C++20</td>
<td>const &#37325;&#36733;&#33021;&#20197;&#19981;&#20855;&#22823;&#23567;&#33539;&#22260;&#35843;&#29992;</td>
<td>const &#37325;&#36733;&#35201;&#27714; <code>sized_range</code></td>
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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-drop_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>
<td>&#36820;&#22238;&#25351;&#21521;&#26411;&#23614;&#30340;&#36845;&#20195;&#22120;&#25110;&#21736;&#20301;<br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
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<div class="t-dsc-member-div">
<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>
</div>
</td>
<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 class="t-dsc-member-div">
<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>
</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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<div class="visualClear"></div>
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