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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::counted_iterator&lt;I&gt;::</span>operator++,+,+=,--,-,-=</h1>
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<div id="contentSub"><span class="subpages">&lt; <a href="cpp.html">cpp</a>&lrm; | <a href="cpp-iterator.html">iterator</a>&lrm; | <a href="cpp-iterator-counted_iterator.html">counted iterator</a></span></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> counted_iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</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">decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">++</span><span class="br0">(</span> <span class="kw4">int</span> <span class="br0">)</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> counted_iterator operator<span class="sy2">++</span><span class="br0">(</span> <span class="kw4">int</span> <span class="br0">)</span><br />
&nbsp; requires std<span class="sy4">::</span><span class="me2">forward_iterator</span><span class="sy1">&lt;</span>I<span class="sy1">&gt;</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> counted_iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span><br />
&nbsp; requires std<span class="sy4">::</span><span class="me2">bidirectional_iterator</span><span class="sy1">&lt;</span>I<span class="sy1">&gt;</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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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> counted_iterator operator<span class="sy2">--</span><span class="br0">(</span> <span class="kw4">int</span> <span class="br0">)</span><br />
&nbsp; requires std<span class="sy4">::</span><span class="me2">bidirectional_iterator</span><span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span></span></div>
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<td>(5)</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> counted_iterator operator<span class="sy2">+</span><span class="br0">(</span> std<span class="sy4">::</span><span class="me2">iter_difference_t</span><span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n <span class="br0">)</span> <span class="kw4">const</span><br />
&nbsp; requires std<span class="sy4">::</span><span class="me2">random_access_iterator</span><span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span></span></div>
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<td>(6)</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> counted_iterator<span class="sy3">&amp;</span> operator<span class="sy2">+</span><span class="sy1">=</span><span class="br0">(</span> std<span class="sy4">::</span><span class="me2">iter_difference_t</span><span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n <span class="br0">)</span><br />
&nbsp; requires std<span class="sy4">::</span><span class="me2">random_access_iterator</span><span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span></span></div>
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<td>(7)</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> counted_iterator operator<span class="sy2">-</span><span class="br0">(</span> std<span class="sy4">::</span><span class="me2">iter_difference_t</span><span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n <span class="br0">)</span> <span class="kw4">const</span><br />
&nbsp; requires std<span class="sy4">::</span><span class="me2">random_access_iterator</span><span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span></span></div>
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<td>(8)</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> counted_iterator<span class="sy3">&amp;</span> operator<span class="sy2">-</span><span class="sy1">=</span><span class="br0">(</span> std<span class="sy4">::</span><span class="me2">iter_difference_t</span><span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n <span class="br0">)</span><br />
&nbsp; requires std<span class="sy4">::</span><span class="me2">random_access_iterator</span><span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span></span></div>
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<td>(9)</td>
<td><span class="t-mark-rev t-since-cxx20">(C++20 &#36215;)</span></td>
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<p>&#22686;&#25110;&#20943;&#24213;&#23618;&#36845;&#20195;&#22120; <code><i>current</i></code> &#21644;&#21040;&#26411;&#23614;&#30340;&#36317;&#31163; <code><i>length</i></code> &#12290;</p>
<p>&#33509; <code><i>length</i></code> &#20250;&#34987;&#35774;&#20026;&#36127;&#20540;&#21017;&#36825;&#20123;&#20989;&#25968;&#23548;&#33268;&#26410;&#23450;&#20041;&#34892;&#20026;&#12290;</p>
<div class="t-li1"><span class="t-li">1)</span> &#21069;&#33258;&#22686;&#19968;&#12290;&#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">++</span>current<span class="sy4">;</span> <span class="sy2">--</span>length<span class="sy4">;</span> <span class="kw1">return</span> <span class="sy2">*</span>this<span class="sy4">;</span></span></span> &#12290;</div>
<div class="t-li1"><span class="t-li">2)</span> &#21518;&#33258;&#22686;&#19968;&#12290;&#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">--</span>length<span class="sy4">;</span> <span class="kw1">try</span> <span class="br0">{</span> <span class="kw1">return</span> current<span class="sy2">++</span><span class="sy4">;</span> <span class="br0">}</span> <span class="kw1">catch</span><span class="br0">(</span>...<span class="br0">)</span> <span class="br0">{</span> <span class="sy2">++</span>length<span class="sy4">;</span> <span class="kw1">throw</span><span class="sy4">;</span> <span class="br0">}</span></span></span> &#12290;</div>
<div class="t-li1"><span class="t-li">3)</span> &#21518;&#33258;&#22686;&#19968;&#12290;&#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp">counted_iterator temp<span class="br0">{</span><span class="sy2">*</span>this<span class="br0">}</span><span class="sy4">;</span> <span class="sy2">++*</span>this<span class="sy4">;</span> <span class="kw1">return</span> temp<span class="sy4">;</span></span></span> &#12290;</div>
<div class="t-li1"><span class="t-li">4)</span> &#21069;&#33258;&#20943;&#19968;&#12290;&#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">--</span>current<span class="sy4">;</span> <span class="sy2">++</span>length<span class="sy4">;</span> <span class="kw1">return</span> <span class="sy2">*</span>this<span class="sy4">;</span></span></span> &#12290;</div>
<div class="t-li1"><span class="t-li">5)</span> &#21518;&#33258;&#20943;&#19968;&#12290;&#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp">counted_iterator temp<span class="br0">{</span><span class="sy2">*</span>this<span class="br0">}</span><span class="sy4">;</span> <span class="sy2">--*</span>this<span class="sy4">;</span> <span class="kw1">return</span> temp<span class="sy4">;</span></span></span> &#12290;</div>
<div class="t-li1"><span class="t-li">6)</span> &#36820;&#22238;&#21069;&#36827; <code>n</code> &#30340;&#36845;&#20195;&#22120;&#12290;&#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">return</span> counted_iterator<span class="br0">(</span>current <span class="sy2">+</span> n, length <span class="sy2">-</span> n<span class="br0">)</span><span class="sy4">;</span></span></span> &#12290;</div>
<div class="t-li1"><span class="t-li">7)</span> &#20196;&#36845;&#20195;&#22120;&#21069;&#36827; <code>n</code> &#12290;&#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp">current <span class="sy2">+</span><span class="sy1">=</span> n<span class="sy4">;</span> length <span class="sy2">-</span><span class="sy1">=</span> n<span class="sy4">;</span> <span class="kw1">return</span> <span class="sy2">*</span>this<span class="sy4">;</span></span></span> &#12290;</div>
<div class="t-li1"><span class="t-li">8)</span> &#36820;&#22238;&#21069;&#36827; <code>-n</code> &#30340;&#36845;&#20195;&#22120;&#12290;&#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">return</span> counted_iterator<span class="br0">(</span>current <span class="sy2">-</span> n, length <span class="sy2">+</span> n<span class="br0">)</span><span class="sy4">;</span></span></span> &#12290;</div>
<div class="t-li1"><span class="t-li">9)</span> &#20196;&#36845;&#20195;&#22120;&#21069;&#36827; <code>-n</code> &#12290;&#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp">current <span class="sy2">-</span><span class="sy1">=</span> n<span class="sy4">;</span> length <span class="sy2">+</span><span class="sy1">=</span> n<span class="sy4">;</span> <span class="kw1">return</span> <span class="sy2">*</span>this<span class="sy4">;</span></span></span> &#12290;</div>
<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">&#21442;&#25968;</span></h3>
<table class="t-par-begin">
<tr class="t-par">
<td>n</td>
<td>-</td>
<td>&#35201;&#22686;&#25110;&#20943;&#36845;&#20195;&#22120;&#36866;&#37197;&#22120;&#30340;&#20301;&#32622;&#25968;</td>
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<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">&#36820;&#22238;&#20540;</span></h3>
<div class="t-li1"><span class="t-li">1)</span> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this</span></span> &#12290;</div>
<div class="t-li1"><span class="t-li">2-3)</span> &#26356;&#25913;&#21069;&#21019;&#24314;&#30340; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this</span></span> &#21103;&#26412;&#12290;</div>
<div class="t-li1"><span class="t-li">4)</span> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this</span></span> &#12290;</div>
<div class="t-li1"><span class="t-li">5)</span> &#26356;&#25913;&#21069;&#21019;&#24314;&#30340; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this</span></span> &#21103;&#26412;&#12290;</div>
<div class="t-li1"><span class="t-li">6)</span> &#21069;&#36827; <span class="t-c"><span class="mw-geshi cpp source-cpp">n</span></span> &#30340;&#36845;&#20195;&#22120;&#36866;&#37197;&#22120;&#12290;</div>
<div class="t-li1"><span class="t-li">7)</span> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this</span></span> &#12290;</div>
<div class="t-li1"><span class="t-li">8)</span> &#21069;&#36827; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">-</span>n</span></span> &#30340;&#36845;&#20195;&#22120;&#36866;&#37197;&#22120;&#12290;</div>
<div class="t-li1"><span class="t-li">9)</span> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this</span></span> &#12290;</div>
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">&#31034;&#20363;</span></h3>
<div class="t-example">
<div class="t-example-live-link"></div>
<div dir="ltr" class="mw-geshi" style="text-align: left;">
<div class="cpp source-cpp">
<pre class="de1"><span class="co2">#include &lt;cassert&gt;</span>
<span class="co2">#include &lt;initializer_list&gt;</span>
<span class="co2">#include &lt;iterator&gt;</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
<span class="kw4">const</span> <span class="kw4">auto</span> v <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="nu0">6</span><span class="br0">}</span><span class="sy4">;</span>
std<span class="sy4">::</span><span class="me2">counted_iterator</span><span class="sy1">&lt;</span><a href="cpp-utility-initializer_list.html"><span class="kw960">std::<span class="me2">initializer_list</span></span></a><span class="sy1">&lt;</span><span class="kw4">int</span><span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">iterator</span><span class="sy1">&gt;</span> it1 <span class="br0">{</span>v.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span>, <span class="nu0">5</span><span class="br0">}</span><span class="sy4">;</span>
<span class="sy2">++</span>it1<span class="sy4">;</span> <a href="cpp-error-assert.html"><span class="kw774">assert</span></a><span class="br0">(</span><span class="sy2">*</span>it1 <span class="sy1">==</span> <span class="nu0">2</span> <span class="sy3">&amp;&amp;</span> it1.<span class="me1">count</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="co1">// (1)</span>
<span class="kw4">auto</span> it2 <span class="sy1">=</span> it1<span class="sy2">++</span><span class="sy4">;</span> <a href="cpp-error-assert.html"><span class="kw774">assert</span></a><span class="br0">(</span><span class="sy2">*</span>it2 <span class="sy1">==</span> <span class="nu0">2</span> <span class="sy3">&amp;&amp;</span> <span class="sy2">*</span>it1 <span class="sy1">==</span> <span class="nu0">3</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// (3)</span>
<span class="sy2">--</span>it1<span class="sy4">;</span> <a href="cpp-error-assert.html"><span class="kw774">assert</span></a><span class="br0">(</span><span class="sy2">*</span>it1 <span class="sy1">==</span> <span class="nu0">2</span> <span class="sy3">&amp;&amp;</span> it1.<span class="me1">count</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="co1">// (4)</span>
<span class="kw4">auto</span> it3 <span class="sy1">=</span> it1<span class="sy2">--</span><span class="sy4">;</span> <a href="cpp-error-assert.html"><span class="kw774">assert</span></a><span class="br0">(</span><span class="sy2">*</span>it3 <span class="sy1">==</span> <span class="nu0">2</span> <span class="sy3">&amp;&amp;</span> <span class="sy2">*</span>it1 <span class="sy1">==</span> <span class="nu0">1</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// (5)</span>
<span class="kw4">auto</span> it4 <span class="sy1">=</span> it1 <span class="sy2">+</span> <span class="nu0">3</span><span class="sy4">;</span> <a href="cpp-error-assert.html"><span class="kw774">assert</span></a><span class="br0">(</span><span class="sy2">*</span>it4 <span class="sy1">==</span> <span class="nu0">4</span> <span class="sy3">&amp;&amp;</span> it4.<span class="me1">count</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">==</span> <span class="nu0">2</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// (6)</span>
<span class="kw4">auto</span> it5 <span class="sy1">=</span> it4 <span class="sy2">-</span> <span class="nu0">3</span><span class="sy4">;</span> <a href="cpp-error-assert.html"><span class="kw774">assert</span></a><span class="br0">(</span><span class="sy2">*</span>it5 <span class="sy1">==</span> <span class="nu0">1</span> <span class="sy3">&amp;&amp;</span> it5.<span class="me1">count</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="co1">// (8)</span>
it1 <span class="sy2">+</span><span class="sy1">=</span> <span class="nu0">3</span><span class="sy4">;</span> <a href="cpp-error-assert.html"><span class="kw774">assert</span></a><span class="br0">(</span><span class="sy2">*</span>it1 <span class="sy1">==</span> <span class="nu0">4</span> <span class="sy3">&amp;&amp;</span> it1.<span class="me1">count</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">==</span> <span class="nu0">2</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// (7)</span>
it1 <span class="sy2">-</span><span class="sy1">=</span> <span class="nu0">3</span><span class="sy4">;</span> <a href="cpp-error-assert.html"><span class="kw774">assert</span></a><span class="br0">(</span><span class="sy2">*</span>it1 <span class="sy1">==</span> <span class="nu0">1</span> <span class="sy3">&amp;&amp;</span> it1.<span class="me1">count</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="co1">// (9)</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 class="t-dsc-member-div">
<div><a href="cpp-iterator-counted_iterator-operator+.html"><span class="t-lines"><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>
</div>
</td>
<td>&#20196;&#36845;&#20195;&#22120;&#21069;&#36827;<br />
<span class="t-mark">(&#20989;&#25968;&#27169;&#26495;)</span></td>
</tr>
<tr class="t-dsc">
<td>
<div class="t-dsc-member-div">
<div><a href="cpp-iterator-counted_iterator-operator-.html"><span class="t-lines"><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>
</div>
</td>
<td>&#35745;&#31639;&#20004;&#20010;&#36845;&#20195;&#22120;&#36866;&#37197;&#22120;&#38388;&#30340;&#36317;&#31163;<br />
<span class="t-mark">(&#20989;&#25968;&#27169;&#26495;)</span></td>
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<div class="visualClear"></div>
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