85 lines
5.7 KiB
HTML
85 lines
5.7 KiB
HTML
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<title>std::chrono::duration<Rep,Period>::count</title>
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::chrono::duration<Rep,Period>::</span>count</h1>
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<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-chrono.html">chrono</a>‎ | <a href="cpp-chrono-duration.html">duration</a></span></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> rep count<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></span></div>
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<p>返回此 duration 的计次数。</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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<p>（无）</p>
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<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">返回值</span></h3>
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<p>此 duration 的计次数。</p>
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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 <chrono></span>
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<span class="co2">#include <iostream></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-chrono-duration.html"><span class="kw996">std::<span class="me2">chrono</span><span class="sy4">::</span><span class="me2">milliseconds</span></span></a> ms<span class="br0">{</span><span class="nu0">3</span><span class="br0">}</span><span class="sy4">;</span> <span class="co1">// 3 毫秒</span>
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<span class="co1">// 从 3 毫秒构造 6000 微秒</span>
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<a href="cpp-chrono-duration.html"><span class="kw995">std::<span class="me2">chrono</span><span class="sy4">::</span><span class="me2">microseconds</span></span></a> us <span class="sy1">=</span> <span class="nu0">2</span><span class="sy2">*</span>ms<span class="sy4">;</span>
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<span class="co1">// 使用分数计次的 30Hz 时钟</span>
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<a href="cpp-chrono-duration.html"><span class="kw993">std::<span class="me2">chrono</span><span class="sy4">::</span><span class="me2">duration</span></span></a><span class="sy1"><</span><span class="kw4">double</span>, <a href="cpp-numeric-ratio-ratio.html"><span class="kw1522">std::<span class="me2">ratio</span></span></a><span class="sy1"><</span><span class="nu0">1</span>, <span class="nu0">30</span><span class="sy1">>></span> hz30<span class="br0">(</span><span class="nu16">3.5</span><span class="br0">)</span><span class="sy4">;</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> <span class="st0">"3 ms duration has "</span> <span class="sy1"><<</span> ms.<span class="me1">count</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">" ticks<span class="es1">\n</span>"</span>
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<span class="sy1"><<</span> <span class="st0">"6000 us duration has "</span> <span class="sy1"><<</span> us.<span class="me1">count</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">" ticks<span class="es1">\n</span>"</span>
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<span class="sy1"><<</span> <span class="st0">"3.5 30Hz duration has "</span> <span class="sy1"><<</span> hz30.<span class="me1">count</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">" ticks<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">3 ms duration has 3 ticks
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6000 us duration has 6000 ticks
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3.5 30Hz duration has 3.5 ticks</pre></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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<div><a href="cpp-chrono-duration-duration_cast.html"><span class="t-lines"><span>duration_cast</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div>
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<td>转换时长到另一个拥有不同嘀嗒间隔的时长<br />
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<span class="t-mark">(函数模板)</span></td>
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