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<title>std::chrono::year_month_weekday_last::operator+=, std::chrono::year_month_weekday_last::operator-=</title>
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::chrono::year_month_weekday_last::</span>operator+=, <span style="font-size:0.7em; line-height:130%">std::chrono::year_month_weekday_last::</span>operator-=</h1>
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<div id="contentSub"><span class="subpages">&lt; <a href="cpp.html">cpp</a>&lrm; | <a href="cpp-chrono.html">chrono</a>&lrm; | <a href="cpp-chrono-year_month_weekday_last.html">year month weekday last</a></span></div>
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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">chrono</span><span class="sy4">::</span><span class="me2">year_month_weekday_last</span><span class="sy3">&amp;</span> operator<span class="sy2">+</span><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">years</span><span class="sy3">&amp;</span> dy<span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</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> std<span class="sy4">::</span><span class="me2">chrono</span><span class="sy4">::</span><span class="me2">year_month_weekday_last</span><span class="sy3">&amp;</span> operator<span class="sy2">+</span><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">months</span><span class="sy3">&amp;</span> dm<span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</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><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> std<span class="sy4">::</span><span class="me2">chrono</span><span class="sy4">::</span><span class="me2">year_month_weekday_last</span><span class="sy3">&amp;</span> operator<span class="sy2">-</span><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">years</span><span class="sy3">&amp;</span> dy<span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span></span></div>
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<td>(3)</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> std<span class="sy4">::</span><span class="me2">chrono</span><span class="sy4">::</span><span class="me2">year_month_weekday_last</span><span class="sy3">&amp;</span> operator<span class="sy2">-</span><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">months</span><span class="sy3">&amp;</span> dm<span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span></span></div>
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<td>(4)</td>
<td><span class="t-mark-rev t-since-cxx20">(C++20 &#36215;)</span></td>
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<p>&#20197;&#26102;&#38271; <code>dy</code> &#25110; <code>dm</code> &#20026;&#31243;&#24230;&#20462;&#25913;&#26102;&#38388;&#28857; <code>*this</code> &#12290;</p>
<div class="t-li1"><span class="t-li">1)</span> &#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this <span class="sy1">=</span> <span class="sy2">*</span>this <span class="sy2">+</span> dy<span class="sy4">;</span></span></span></div>
<div class="t-li1"><span class="t-li">2)</span> &#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this <span class="sy1">=</span> <span class="sy2">*</span>this <span class="sy2">+</span> dm<span class="sy4">;</span></span></span></div>
<div class="t-li1"><span class="t-li">3)</span> &#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this <span class="sy1">=</span> <span class="sy2">*</span>this <span class="sy2">-</span> dy<span class="sy4">;</span></span></span></div>
<div class="t-li1"><span class="t-li">4)</span> &#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this <span class="sy1">=</span> <span class="sy2">*</span>this <span class="sy2">-</span> dm<span class="sy4">;</span></span></span></div>
<p>&#23545;&#20110;&#33021;&#36716;&#25442;&#21040; <span class="t-lc">std::chrono::years</span> &#19982; <span class="t-lc">std::chrono::months</span> &#20004;&#32773;&#30340;&#26102;&#38271;&#65292;&#33509;&#35843;&#29992;&#26377;&#27495;&#20041;&#65292;&#21017;&#20559;&#22909; <code>years</code> &#37325;&#36733; <span class="t-v">(1,3)</span> &#12290;</p>
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">&#21442;&#38405;</span></h3>
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<div><a href="cpp-chrono-year_month_weekday_last-operator_arith_2.html"><span class="t-lines"><span>operator+</span><span>operator-</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>&#23558; <code>year_month_weekday_last</code> &#19982;&#19968;&#23450;&#25968;&#37327;&#30340; <code>years</code> &#25110; <code>months</code> &#30456;&#21152;&#25110;&#30456;&#20943;<br />
<span class="t-mark">(&#20989;&#25968;)</span></td>
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