90 lines
7.9 KiB
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90 lines
7.9 KiB
HTML
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<title>std::chrono::operator==,<=>(std::chrono::day)</title>
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::chrono::</span>operator==,<=><span style="font-size:0.7em; line-height:130%">(std::chrono::day)</span></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-day.html">day</a></span></div>
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<div>定义于头文件 <code><a href="cpp-header-chrono.html"><chrono></a></code></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span> <span class="kw4">const</span> std<span class="sy4">::</span><span class="me2">chrono</span><span class="sy4">::</span><span class="me2">day</span><span class="sy3">&</span> x,<br />
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<span class="kw4">const</span> std<span class="sy4">::</span><span class="me2">chrono</span><span class="sy4">::</span><span class="me2">day</span><span class="sy3">&</span> y <span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span></span></div>
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<td>(1)</td>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> std<span class="sy4">::</span><span class="me2">strong_ordering</span> operator<span class="sy1"><=></span><span class="br0">(</span> <span class="kw4">const</span> std<span class="sy4">::</span><span class="me2">chrono</span><span class="sy4">::</span><span class="me2">day</span><span class="sy3">&</span> x,<br />
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<span class="kw4">const</span> std<span class="sy4">::</span><span class="me2">chrono</span><span class="sy4">::</span><span class="me2">day</span><span class="sy3">&</span> y <span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span></span></div>
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<td>(2)</td>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span></td>
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<p>比较二个 <span class="t-lc">std::chrono::day</span> <code>x</code> 和 <code>y</code> 。</p>
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<p><code><</code>、 <code><=</code>、 <code>></code>、 <code>>=</code> 及 <code>!=</code> 运算符分别从 <code>operator<=></code> 与 <code>operator==</code> <a href="cpp-language-operators.html#.E5.85.B3.E7.B3.BB.E8.BF.90.E7.AE.97.E7.AC.A6">合成</a>。</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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<div class="t-li1"><span class="t-li">1)</span> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">unsigned</span><span class="br0">(</span>x<span class="br0">)</span> <span class="sy1">==</span> <span class="kw4">unsigned</span><span class="br0">(</span>y<span class="br0">)</span></span></span></div>
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<div class="t-li1"><span class="t-li">2)</span> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">unsigned</span><span class="br0">(</span>x<span class="br0">)</span> <span class="sy1"><=></span> <span class="kw4">unsigned</span><span class="br0">(</span>y<span class="br0">)</span></span></span></div>
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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 <iostream></span>
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<span class="co2">#include <chrono></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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std<span class="sy4">::</span><span class="me2">chrono</span><span class="sy4">::</span><span class="me2">day</span> d1<span class="br0">{</span><span class="nu0">15</span><span class="br0">}</span><span class="sy4">;</span>
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std<span class="sy4">::</span><span class="me2">chrono</span><span class="sy4">::</span><span class="me2">day</span> d2<span class="br0">{</span><span class="nu0">20</span><span class="br0">}</span><span class="sy4">;</span>
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d1 <span class="sy1">==</span> d2 <span class="sy4">?</span> <a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"d1 and d2 are equal<span class="es1">\n</span>"</span>
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<span class="sy4">:</span> <a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"d1 and d2 are not equal<span class="es1">\n</span>"</span><span class="sy4">;</span>
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<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="me2">chrono_literals</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> <a href="cpp-io-manip-boolalpha.html"><span class="kw1764">std::<span class="me2">boolalpha</span></span></a>
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<span class="sy1"><<</span> <span class="br0">(</span>6d <span class="sy1"><</span> 9d<span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">' '</span> <span class="sy1"><<</span> <span class="br0">(</span>6d <span class="sy1">==</span> 6d<span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">' '</span> <span class="sy1"><<</span> <span class="br0">(</span>6d <span class="sy1"><=</span> 9d<span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">' '</span>
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<span class="sy1"><<</span> <span class="br0">(</span>9d <span class="sy1">></span> 6d<span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">' '</span> <span class="sy1"><<</span> <span class="br0">(</span>9d <span class="sy3">!</span><span class="sy1">=</span> 6d<span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">' '</span> <span class="sy1"><<</span> <span class="br0">(</span>9d <span class="sy1">>=</span> 6d<span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">'<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">d1 and d2 are not equal
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true true true true true true</pre></div>
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