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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::</span>iterator</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></span></div>
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<div>&#23450;&#20041;&#20110;&#22836;&#25991;&#20214; <code><a href="cpp-header-iterator.html">&lt;iterator&gt;</a></code></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span><br /></span>
<p>&nbsp; &nbsp; <span class="kw1">class</span> Category,<br />
&nbsp; &nbsp; <span class="kw1">class</span> T,<br />
&nbsp; &nbsp; <span class="kw1">class</span> Distance <span class="sy1">=</span> <a href="cpp-types-ptrdiff_t.html"><span class="kw101">std::<span class="me2">ptrdiff_t</span></span></a>,<br />
&nbsp; &nbsp; <span class="kw1">class</span> Pointer <span class="sy1">=</span> T<span class="sy2">*</span>,<br />
&nbsp; &nbsp; <span class="kw1">class</span> Reference <span class="sy1">=</span> T<span class="sy3">&amp;</span><br /></p>
<span class="sy1">&gt;</span> <span class="kw1">struct</span> iterator<span class="sy4">;</span></div>
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<td><span class="t-mark">(C++17 &#20013;&#24323;&#29992;)</span></td>
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<p><code>std::iterator</code> &#26159;&#25552;&#20379;&#20197;&#31616;&#21270;&#36845;&#20195;&#22120;&#25152;&#35201;&#27714;&#31867;&#22411;&#23450;&#20041;&#30340;&#22522;&#31867;&#12290;</p>
<h3><span class="mw-headline" id=".E6.A8.A1.E6.9D.BF.E5.BD.A2.E5.8F.82">&#27169;&#26495;&#24418;&#21442;</span></h3>
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<td>Category</td>
<td>-</td>
<td>&#36845;&#20195;&#22120;&#31867;&#21035;&#12290;&#24517;&#39035;&#26159;<a href="cpp-iterator-iterator_tags.html">&#36845;&#20195;&#22120;&#31867;&#21035;&#26631;&#31614;</a>&#20043;&#19968;&#12290;</td>
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<td>T</td>
<td>-</td>
<td>&#33021;&#36890;&#36807;&#35299;&#24341;&#29992;&#36845;&#20195;&#22120;&#33719;&#24471;&#30340;&#20540;&#30340;&#31867;&#22411;&#12290;&#27492;&#31867;&#22411;&#23545;&#20110;&#36755;&#20986;&#36845;&#20195;&#22120;&#24212;&#20026; <code>void</code> &#12290;</td>
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<td>Distance</td>
<td>-</td>
<td>&#33021;&#29992;&#20110;&#26631;&#35782;&#36845;&#20195;&#22120;&#38388;&#36317;&#31163;&#30340;&#31867;&#22411;</td>
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<td>Pointer</td>
<td>-</td>
<td>&#23450;&#20041;&#25351;&#21521;&#34987;&#36845;&#20195;&#30340;&#31867;&#22411;&#65288; <code>T</code> &#65289;&#30340;&#25351;&#38024;</td>
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<td>Reference</td>
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<td>&#23450;&#20041;&#21040;&#34987;&#36845;&#20195;&#30340;&#31867;&#22411;&#65288; <code>T</code> &#65289;&#30340;&#24341;&#29992;</td>
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<h3><span class="mw-headline" id=".E6.88.90.E5.91.98.E7.B1.BB.E5.9E.8B">&#25104;&#21592;&#31867;&#22411;</span></h3>
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<td>&#25104;&#21592;&#31867;&#22411;</td>
<td>&#23450;&#20041;</td>
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<td><code>iterator_category</code></td>
<td><code>Category</code></td>
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<td><code>value_type</code></td>
<td><code>T</code></td>
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<td><code>difference_type</code></td>
<td><code>Distance</code></td>
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<td><code>pointer</code></td>
<td><code>Pointer</code></td>
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<td><code>reference</code></td>
<td><code>Reference</code></td>
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<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">&#31034;&#20363;</span></h3>
<div class="t-example">
<p>&#20197;&#19979;&#31034;&#20363;&#28436;&#31034;&#22914;&#20309;&#36890;&#36807;&#32487;&#25215; <code>std::iterator</code> &#23454;&#29616;<a href="cpp-named_req-InputIterator.html">&#36755;&#20837;&#36845;&#20195;&#22120;</a></p>
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<pre class="de1"><span class="co2">#include &lt;iostream&gt;</span>
<span class="co2">#include &lt;algorithm&gt;</span>
<span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw4">long</span> FROM, <span class="kw4">long</span> TO<span class="sy1">&gt;</span>
<span class="kw1">class</span> Range <span class="br0">{</span>
<span class="kw1">public</span><span class="sy4">:</span>
<span class="co1">// &#36890;&#36807;&#32487;&#25215;&#33258; std::iterator &#25552;&#20379;&#25104;&#21592; typedef</span>
<span class="kw1">class</span> iterator<span class="sy4">:</span> <span class="kw1">public</span> std<span class="sy4">::</span><span class="me2">iterator</span><span class="sy1">&lt;</span>
<a href="cpp-iterator-iterator_tags.html"><span class="kw652">std::<span class="me2">input_iterator_tag</span></span></a>, <span class="co1">// iterator_category</span>
<span class="kw4">long</span>, <span class="co1">// value_type</span>
<span class="kw4">long</span>, <span class="co1">// difference_type</span>
<span class="kw4">const</span> <span class="kw4">long</span><span class="sy2">*</span>, <span class="co1">// pointer</span>
<span class="kw4">long</span> <span class="co1">// reference</span>
<span class="sy1">&gt;</span><span class="br0">{</span>
<span class="kw4">long</span> num <span class="sy1">=</span> FROM<span class="sy4">;</span>
<span class="kw1">public</span><span class="sy4">:</span>
<span class="kw1">explicit</span> iterator<span class="br0">(</span><span class="kw4">long</span> _num <span class="sy1">=</span> <span class="nu0">0</span><span class="br0">)</span> <span class="sy4">:</span> num<span class="br0">(</span>_num<span class="br0">)</span> <span class="br0">{</span><span class="br0">}</span>
iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>num <span class="sy1">=</span> TO <span class="sy1">&gt;=</span> FROM <span class="sy4">?</span> num <span class="sy2">+</span> <span class="nu0">1</span><span class="sy4">:</span> num <span class="sy2">-</span> <span class="nu0">1</span><span class="sy4">;</span> <span class="kw1">return</span> <span class="sy2">*</span>this<span class="sy4">;</span><span class="br0">}</span>
iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span> <span class="br0">{</span>iterator retval <span class="sy1">=</span> <span class="sy2">*</span>this<span class="sy4">;</span> <span class="sy2">++</span><span class="br0">(</span><span class="sy2">*</span>this<span class="br0">)</span><span class="sy4">;</span> <span class="kw1">return</span> retval<span class="sy4">;</span><span class="br0">}</span>
<span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span>iterator other<span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span><span class="kw1">return</span> num <span class="sy1">==</span> other.<span class="me1">num</span><span class="sy4">;</span><span class="br0">}</span>
<span class="kw4">bool</span> operator<span class="sy3">!</span><span class="sy1">=</span><span class="br0">(</span>iterator other<span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span><span class="kw1">return</span> <span class="sy3">!</span><span class="br0">(</span><span class="sy2">*</span>this <span class="sy1">==</span> other<span class="br0">)</span><span class="sy4">;</span><span class="br0">}</span>
reference operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span><span class="kw1">return</span> num<span class="sy4">;</span><span class="br0">}</span>
<span class="br0">}</span><span class="sy4">;</span>
iterator begin<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span><span class="kw1">return</span> iterator<span class="br0">(</span>FROM<span class="br0">)</span><span class="sy4">;</span><span class="br0">}</span>
iterator end<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span><span class="kw1">return</span> iterator<span class="br0">(</span>TO <span class="sy1">&gt;=</span> FROM<span class="sy4">?</span> TO<span class="sy2">+</span><span class="nu0">1</span> <span class="sy4">:</span> TO<span class="sy2">-</span><span class="nu0">1</span><span class="br0">)</span><span class="sy4">;</span><span class="br0">}</span>
<span class="br0">}</span><span class="sy4">;</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
<span class="co1">// std::find &#35201;&#27714;&#36755;&#20837;&#36845;&#20195;&#22120;</span>
<span class="kw4">auto</span> range <span class="sy1">=</span> Range<span class="sy1">&lt;</span><span class="nu0">15</span>, <span class="nu0">25</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw4">auto</span> itr <span class="sy1">=</span> <a href="cpp-algorithm-find_if_not.html"><span class="kw1573">std::<span class="me2">find</span></span></a><span class="br0">(</span>range.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span>, range.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span>, <span class="nu0">18</span><span class="br0">)</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1757">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="sy2">*</span>itr <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span> <span class="co1">// 18</span>
<span class="co1">// Range::iterator &#20134;&#28385;&#36275;&#22522;&#20110;&#33539;&#22260;&#30340; for &#35201;&#27714;</span>
<span class="kw1">for</span><span class="br0">(</span><span class="kw4">long</span> l <span class="sy4">:</span> Range<span class="sy1">&lt;</span><span class="nu0">3</span>, <span class="nu0">5</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span>
<a href="cpp-io-cout.html"><span class="kw1757">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> l <span class="sy1">&lt;&lt;</span> <span class="st0">&#39; &#39;</span><span class="sy4">;</span> <span class="co1">// 3 4 5</span>
<span class="br0">}</span>
<a href="cpp-io-cout.html"><span class="kw1757">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">18
3 4 5</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><a href="cpp-iterator-iterator_traits.html"><span class="t-lines"><span>iterator_traits</span></span></a></div>
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<td>&#20026;&#36845;&#20195;&#22120;&#21508;&#39033;&#24615;&#36136;&#25552;&#20379;&#32479;&#19968;&#25509;&#21475;<br />
<span class="t-mark">(&#31867;&#27169;&#26495;)</span></td>
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<div><a href="cpp-iterator-iterator_tags.html"><span class="t-lines"><span>input_iterator_tag</span><span>output_iterator_tag</span><span>forward_iterator_tag</span><span>bidirectional_iterator_tag</span><span>random_access_iterator_tag</span><span>contiguous_iterator_tag</span></span></a></div>
<div><span class="t-lines"><span></span><span></span><span></span><span></span><span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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<td>&#29992;&#20110;&#25351;&#31034;&#36845;&#20195;&#22120;&#31867;&#21035;&#30340;&#31354;&#31867;&#31867;&#22411;<br />
<span class="t-mark">(&#31867;)</span></td>
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