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<h1 id="firstHeading" class="firstHeading">&#30452;&#25509;&#21021;&#22987;&#21270;</h1>
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<div id="contentSub"><span class="subpages">&lt; <a href="cpp.html">cpp</a>&lrm; | <a href="cpp-language.html">language</a></span></div>
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<p>&#20174;&#26126;&#30830;&#30340;&#26500;&#36896;&#20989;&#25968;&#23454;&#21442;&#30340;&#38598;&#21512;&#21021;&#22987;&#21270;&#23545;&#35937;&#12290;</p>
<h3><span class="mw-headline" id=".E8.AF.AD.E6.B3.95">&#35821;&#27861;</span></h3>
<table class="t-sdsc-begin">
<tr>
<td colspan="10" class="t-sdsc-sep"></td>
</tr>
<tr class="t-sdsc">
<td><span class="t-spar">T</span> <span class="t-spar">&#23545;&#35937;</span> <code><b>(</b></code> <span class="t-spar">&#23454;&#21442;</span> <code><b>);</b></code>
<p><span class="t-spar">T</span> <span class="t-spar">&#23545;&#35937;</span> <code><b>(</b></code> <span class="t-spar">&#23454;&#21442;1, &#23454;&#21442;2, ...</span> <code><b>);</b></code></p>
</td>
<td>(1)</td>
<td class="t-sdsc-nopad"></td>
</tr>
<tr>
<td colspan="10" class="t-sdsc-sep"></td>
</tr>
<tr class="t-sdsc">
<td><span class="t-spar">T</span> <span class="t-spar">&#23545;&#35937;</span> <code><b>{</b></code> <span class="t-spar">&#23454;&#21442;</span> <code><b>};</b></code></td>
<td>(2)</td>
<td><span class="t-mark-rev t-since-cxx11">(C++11 &#36215;)</span></td>
</tr>
<tr>
<td colspan="10" class="t-sdsc-sep"></td>
</tr>
<tr class="t-sdsc">
<td><span class="t-spar">T</span> <code><b>(</b></code> <span class="t-spar">&#20854;&#20182;&#23545;&#35937;</span> <code><b>)</b></code>
<p><span class="t-spar">T</span> <code><b>(</b></code> <span class="t-spar">&#23454;&#21442;1, &#23454;&#21442;2, ...</span> <code><b>)</b></code></p>
</td>
<td>(3)</td>
<td class="t-sdsc-nopad"></td>
</tr>
<tr>
<td colspan="10" class="t-sdsc-sep"></td>
</tr>
<tr class="t-sdsc">
<td><code><b>static_cast&lt;</b></code> <span class="t-spar">T</span> <code><b>&gt;(</b></code> <span class="t-spar">&#20854;&#20182;&#23545;&#35937;</span> <code><b>)</b></code></td>
<td>(4)</td>
<td class="t-sdsc-nopad"></td>
</tr>
<tr>
<td colspan="10" class="t-sdsc-sep"></td>
</tr>
<tr class="t-sdsc">
<td><code><b>new</b></code> <span class="t-spar">T</span><code><b>(</b></code><span class="t-spar">&#23454;&#21442;&#21015;&#34920;, ...</span><code><b>)</b></code></td>
<td>(5)</td>
<td class="t-sdsc-nopad"></td>
</tr>
<tr>
<td colspan="10" class="t-sdsc-sep"></td>
</tr>
<tr class="t-sdsc">
<td><span class="t-spar">&#31867;</span><code><b>::</b></code><span class="t-spar">&#31867;</span><code><b>()</b></code> <code><b>:</b></code> <span class="t-spar">&#25104;&#21592;</span><code><b>(</b></code><span class="t-spar">&#23454;&#21442;&#21015;&#34920;, ...</span><code><b>)</b></code> <code><b>{</b></code> <span class="t-spar">...</span> <code><b>}</b></code></td>
<td>(6)</td>
<td class="t-sdsc-nopad"></td>
</tr>
<tr>
<td colspan="10" class="t-sdsc-sep"></td>
</tr>
<tr class="t-sdsc">
<td><code><b>[</b></code><span class="t-spar">&#23454;&#21442;</span><code><b>](){</b></code> <span class="t-spar">...</span> <code><b>}</b></code></td>
<td>(7)</td>
<td><span class="t-mark-rev t-since-cxx11">(C++11 &#36215;)</span></td>
</tr>
<tr>
<td colspan="10" class="t-sdsc-sep"></td>
</tr>
</table>
<h3><span class="mw-headline" id=".E8.A7.A3.E9.87.8A">&#35299;&#37322;</span></h3>
<p>&#22312;&#19979;&#21015;&#22330;&#21512;&#36827;&#34892;&#30452;&#25509;&#21021;&#22987;&#21270;&#65306;</p>
<div class="t-li1"><span class="t-li">1)</span> &#20197;&#34920;&#36798;&#24335;<span class="t-rev-inl t-since-cxx11"><span>&#25110;&#33457;&#25324;&#21495;&#21021;&#22987;&#21270;&#22120;&#21015;&#34920;</span> <span><span class="t-mark-rev t-since-cxx11">(C++11 &#36215;)</span></span></span>&#30340;&#38750;&#31354;&#24102;&#25324;&#21495;&#21015;&#34920;&#21021;&#22987;&#21270;</div>
<div class="t-li1"><span class="t-li">2)</span> &#20197;&#33457;&#25324;&#21495;&#29615;&#32469;&#30340;&#21333;&#20010;&#21021;&#22987;&#21270;&#22120;&#21021;&#22987;&#21270;&#19968;&#20010;&#38750;&#31867;&#31867;&#22411;&#23545;&#35937;&#65288;&#27880;&#24847;&#65306;&#23545;&#20110;&#31867;&#31867;&#22411;&#21644;&#20854;&#20182;&#20351;&#29992;&#33457;&#25324;&#21495;&#21021;&#22987;&#21270;&#22120;&#21015;&#34920;&#30340;&#21021;&#22987;&#21270;&#65292;&#35265;<a href="cpp-language-list_initialization.html">&#21015;&#34920;&#21021;&#22987;&#21270;</a>&#65289;</div>
<div class="t-li1"><span class="t-li">3)</span> &#29992;<a href="cpp-language-explicit_cast.html">&#20989;&#25968;&#24335;&#36716;&#22411;</a>&#25110;&#20197;&#24102;&#25324;&#21495;&#30340;&#34920;&#36798;&#24335;&#21015;&#34920;&#21021;&#22987;&#21270;<span class="t-rev-inl t-until-cxx17"><span>&#32431;&#21491;&#20540;&#20020;&#26102;&#37327;</span> <span><span class="t-mark-rev t-until-cxx17">(C++17 &#21069;)</span></span></span><span class="t-rev-inl t-since-cxx17"><span>&#32431;&#21491;&#20540;&#30340;&#32467;&#26524;&#23545;&#35937;</span> <span><span class="t-mark-rev t-since-cxx17">(C++17 &#36215;)</span></span></span></div>
<div class="t-li1"><span class="t-li">4)</span> &#29992; <a href="cpp-language-static_cast.html">static_cast</a> &#34920;&#36798;&#24335;&#21021;&#22987;&#21270;<span class="t-rev-inl t-until-cxx17"><span>&#32431;&#21491;&#20540;&#20020;&#26102;&#37327;</span> <span><span class="t-mark-rev t-until-cxx17">(C++17 &#21069;)</span></span></span><span class="t-rev-inl t-since-cxx17"><span>&#32431;&#21491;&#20540;&#30340;&#32467;&#26524;&#23545;&#35937;</span> <span><span class="t-mark-rev t-since-cxx17">(C++17 &#36215;)</span></span></span></div>
<div class="t-li1"><span class="t-li">5)</span> &#29992;&#24102;&#26377;&#38750;&#31354;&#21021;&#22987;&#21270;&#22120;&#30340; new &#34920;&#36798;&#24335;&#21021;&#22987;&#21270;&#20855;&#26377;&#21160;&#24577;&#23384;&#20648;&#26399;&#30340;&#23545;&#35937;</div>
<div class="t-li1"><span class="t-li">6)</span> &#29992;&#26500;&#36896;&#20989;&#25968;<a href="cpp-language-initializer_list.html" class="mw-redirect">&#21021;&#22987;&#21270;&#22120;&#21015;&#34920;</a>&#21021;&#22987;&#21270;&#22522;&#31867;&#25110;&#38750;&#38745;&#24577;&#25104;&#21592;</div>
<div class="t-li1"><span class="t-li">7)</span> &#22312; lambda &#34920;&#36798;&#24335;&#20013;&#20174;&#25353;&#22797;&#21046;&#25429;&#33719;&#30340;&#21464;&#37327;&#21021;&#22987;&#21270;&#38381;&#21253;&#23545;&#35937;&#30340;&#25104;&#21592;</div>
<p>&#30452;&#25509;&#21021;&#22987;&#21270;&#30340;&#25928;&#26524;&#26159;&#65306;</p>
<ul>
<li>&#22914;&#26524; <code>T</code> &#26159;&#25968;&#32452;&#31867;&#22411;&#65292;&#37027;&#20040;</li>
</ul>
<table class="t-rev-begin">
<tr class="t-rev t-until-cxx20">
<td>
<dl>
<dd>
<ul>
<li>&#31243;&#24207;&#38750;&#33391;&#26500;</li>
</ul>
</dd>
</dl>
</td>
<td><span class="t-mark-rev t-until-cxx20">(C++20 &#21069;)</span></td>
</tr>
<tr class="t-rev t-since-cxx20">
<td>
<dl>
<dd>
<ul>
<li>&#25353;<a href="cpp-language-aggregate_initialization.html">&#32858;&#21512;&#21021;&#22987;&#21270;</a>&#21021;&#22987;&#21270;&#25968;&#32452;&#65292;&#20294;&#20801;&#35768;&#31364;&#21270;&#36716;&#25442;&#65292;&#24182;<a href="cpp-language-value_initialization.html">&#20540;&#21021;&#22987;&#21270;</a>&#20219;&#20309;&#19981;&#24102;&#21021;&#22987;&#21270;&#22120;&#30340;&#20803;&#32032;&#12290;</li>
</ul>
</dd>
</dl>
<div dir="ltr" class="mw-geshi" style="text-align: left;">
<div class="cpp source-cpp">
<pre class="de1"><span class="kw1">struct</span> A <span class="br0">{</span> <span class="kw1">explicit</span> A<span class="br0">(</span><span class="kw4">int</span> i <span class="sy1">=</span> <span class="nu0">0</span><span class="br0">)</span> <span class="br0">{</span><span class="br0">}</span> <span class="br0">}</span><span class="sy4">;</span>
A a<span class="br0">[</span><span class="nu0">2</span><span class="br0">]</span><span class="br0">(</span>A<span class="br0">(</span><span class="nu0">1</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// OK&#65306;&#20197; A(1) &#21021;&#22987;&#21270; a[0] &#24182;&#20197; A() &#21021;&#22987;&#21270; a[1]</span>
A b<span class="br0">[</span><span class="nu0">2</span><span class="br0">]</span><span class="br0">{</span>A<span class="br0">(</span><span class="nu0">1</span><span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span> <span class="co1">// &#38169;&#35823;&#65306;&#20174; {} &#38544;&#24335;&#22797;&#21046;&#21021;&#22987;&#21270; b[1] &#36873;&#25321;&#20102; explicit &#26500;&#36896;&#20989;&#25968;</span></pre></div>
</div>
</td>
<td><span class="t-mark-rev t-since-cxx20">(C++20 &#36215;)</span></td>
</tr>
</table>
<ul>
<li>&#22914;&#26524; <code>T</code> &#26159;&#31867;&#31867;&#22411;&#65292;</li>
</ul>
<table class="t-rev-begin">
<tr class="t-rev t-since-cxx17">
<td>
<dl>
<dd>
<ul>
<li>&#22914;&#26524;&#21021;&#22987;&#21270;&#22120;&#26159;<a href="cpp-language-value_category.html">&#32431;&#21491;&#20540;</a>&#34920;&#36798;&#24335;&#19988;&#31867;&#22411;&#19982; <code>T</code> &#20026;&#30456;&#21516;&#30340;&#31867;&#65288;&#24573;&#30053; cv &#38480;&#23450;&#65289;&#65292;&#21017;&#29992;&#21021;&#22987;&#21270;&#22120;&#34920;&#36798;&#24335;&#33258;&#36523;&#65292;&#32780;&#38750;&#20174;&#23427;&#23454;&#36136;&#21270;&#30340;&#20020;&#26102;&#37327;&#65292;&#21021;&#22987;&#21270;&#30446;&#26631;&#23545;&#35937;&#65306;<br />
&#65288; C++17 &#21069;&#65292;&#32534;&#35793;&#22120;&#21487;&#20197;&#22312;&#27492;&#24773;&#20917;&#19979;&#28040;&#38500;&#28304;&#33258;&#32431;&#21491;&#20540;&#30340;&#26500;&#36896;&#65292;&#20294;&#36866;&#21512;&#30340;&#26500;&#36896;&#20989;&#25968;&#20173;&#24517;&#39035;&#21487;&#35775;&#38382;&#65306;&#21442;&#38405;<a href="cpp-language-copy_elision.html">&#22797;&#21046;&#28040;&#38500;</a>&#65289;</li>
</ul>
</dd>
</dl>
</td>
<td><span class="t-mark-rev t-since-cxx17">(C++17 &#36215;)</span></td>
</tr>
</table>
<dl>
<dd>
<ul>
<li>&#26816;&#39564; <code>T</code> &#30340;&#26500;&#36896;&#20989;&#25968;&#24182;&#30001;&#37325;&#36733;&#20915;&#35758;&#36873;&#21462;&#26368;&#20339;&#21305;&#37197;&#12290;&#28982;&#21518;&#35843;&#29992;&#35813;&#26500;&#36896;&#20989;&#25968;&#21021;&#22987;&#21270;&#23545;&#35937;&#12290;</li>
</ul>
</dd>
</dl>
<table class="t-rev-begin">
<tr class="t-rev t-since-cxx20">
<td>
<dl>
<dd>
<ul>
<li>&#21542;&#21017;&#65292;&#22914;&#26524;&#30446;&#26631;&#31867;&#22411;&#26159;&#65288;&#21487;&#33021;&#26377; cv &#38480;&#23450;&#65289;&#30340;&#32858;&#21512;&#31867;&#65292;&#21017;&#25353;<a href="cpp-language-aggregate_initialization.html">&#32858;&#21512;&#21021;&#22987;&#21270;</a>&#20013;&#25152;&#36848;&#36827;&#34892;&#21021;&#22987;&#21270;&#65292;&#20294;&#20801;&#35768;&#31364;&#21270;&#36716;&#25442;&#65292;&#19981;&#20801;&#35768;&#25351;&#27966;&#21021;&#22987;&#21270;&#22120;&#65292;&#19981;&#24310;&#38271;&#24341;&#29992;&#25152;&#32465;&#23450;&#21040;&#30340;&#20020;&#26102;&#37327;&#30340;&#29983;&#23384;&#26399;&#65292;&#19981;&#36827;&#34892;&#33457;&#25324;&#21495;&#28040;&#38500;&#65292;&#24182;<a href="cpp-language-value_initialization.html">&#20540;&#21021;&#22987;&#21270;</a>&#20219;&#20309;&#26080;&#21021;&#22987;&#21270;&#22120;&#30340;&#20803;&#32032;&#12290;</li>
</ul>
</dd>
</dl>
<div dir="ltr" class="mw-geshi" style="text-align: left;">
<div class="cpp source-cpp">
<pre class="de1"><span class="kw1">struct</span> B <span class="br0">{</span>
<span class="kw4">int</span> a<span class="sy4">;</span>
<span class="kw4">int</span><span class="sy3">&amp;&amp;</span> r<span class="sy4">;</span>
<span class="br0">}</span><span class="sy4">;</span>
<span class="kw4">int</span> f<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw4">int</span> n <span class="sy1">=</span> <span class="nu0">10</span><span class="sy4">;</span>
B b1<span class="br0">{</span><span class="nu0">1</span>, f<span class="br0">(</span><span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span> <span class="co1">// OK&#65306;&#24310;&#38271;&#29983;&#23384;&#26399;</span>
B b2<span class="br0">(</span><span class="nu0">1</span>, f<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// &#33391;&#26500;&#65292;&#20294;&#26377;&#24748;&#22402;&#24341;&#29992;</span>
B b3<span class="br0">{</span><span class="nu16">1.0</span>, <span class="nu0">1</span><span class="br0">}</span><span class="sy4">;</span> <span class="co1">// &#38169;&#35823;&#65306;&#31364;&#21270;&#36716;&#25442;</span>
B b4<span class="br0">(</span><span class="nu16">1.0</span>, <span class="nu0">1</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// &#33391;&#26500;&#65292;&#20294;&#26377;&#24748;&#22402;&#24341;&#29992;</span>
B b5<span class="br0">(</span><span class="nu16">1.0</span>, std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>n<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// OK</span></pre></div>
</div>
</td>
<td><span class="t-mark-rev t-since-cxx20">(C++20 &#36215;)</span></td>
</tr>
</table>
<ul>
<li>&#21542;&#21017;&#65292;&#22914;&#26524; <code>T</code> &#26159;&#38750;&#31867;&#31867;&#22411;&#20294;&#28304;&#31867;&#22411;&#26159;&#31867;&#31867;&#22411;&#65292;&#21017;&#26816;&#39564;&#28304;&#31867;&#22411;&#21450;&#20854;&#21508;&#22522;&#31867;&#30340;&#36716;&#25442;&#20989;&#25968;&#65292;&#24182;&#30001;&#37325;&#36733;&#20915;&#35758;&#36873;&#21462;&#26368;&#20339;&#21305;&#37197;&#12290;&#28982;&#21518;&#29992;&#36873;&#21462;&#30340;&#29992;&#25143;&#23450;&#20041;&#36716;&#25442;&#65292;&#36716;&#25442;&#21021;&#22987;&#21270;&#22120;&#34920;&#36798;&#24335;&#20026;&#25152;&#21021;&#22987;&#21270;&#30340;&#23545;&#35937;&#12290;</li>
<li>&#21542;&#21017;&#65292;&#22914;&#26524; <code>T</code> &#26159; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span></span></span> &#32780;&#21407;&#31867;&#22411;&#26159; <span class="t-lc"><a href="cpp-types-nullptr_t.html">std::nullptr_t</a></span>&#65292;&#21017;&#34987;&#21021;&#22987;&#21270;&#23545;&#35937;&#30340;&#20540;&#20026; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">false</span></span></span>&#12290;</li>
<li>&#21542;&#21017;&#65292;&#22312;&#24517;&#35201;&#26102;&#20351;&#29992;<a href="cpp-language-implicit_conversion.html">&#26631;&#20934;&#36716;&#25442;</a>&#65292;&#36716;&#25442; <span class="t-spar">&#20854;&#20182;&#23545;&#35937;</span> &#30340;&#20540;&#20026; <code>T</code> &#30340;&#26080; cv &#38480;&#23450;&#29256;&#26412;&#65292;&#32780;&#25152;&#21021;&#22987;&#21270;&#30340;&#23545;&#35937;&#30340;&#21021;&#20540;&#20026;&#65288;&#21487;&#33021;&#20026;&#36716;&#25442;&#21518;&#30340;&#65289;&#35813;&#20540;&#12290;</li>
</ul>
<h3><span class="mw-headline" id=".E6.B3.A8.E8.A7.A3">&#27880;&#35299;</span></h3>
<p>&#30452;&#25509;&#21021;&#22987;&#27604;&#22797;&#21046;&#21021;&#22987;&#21270;&#26356;&#23485;&#26494;&#65306;&#22797;&#21046;&#21021;&#22987;&#21270;&#20165;&#32771;&#34385;&#38750; <a href="cpp-language-explicit.html">explicit</a> &#26500;&#36896;&#20989;&#25968;&#21644;&#38750; explicit &#30340;&#29992;&#25143;&#23450;&#20041;<a href="cpp-language-cast_operator.html">&#36716;&#25442;&#20989;&#25968;</a>&#65292;&#32780;&#30452;&#25509;&#21021;&#22987;&#21270;&#32771;&#34385;&#25152;&#26377;&#26500;&#36896;&#20989;&#25968;&#21644;&#25152;&#26377;&#29992;&#25143;&#23450;&#20041;&#36716;&#25442;&#20989;&#25968;&#12290;</p>
<p>&#22312;&#20351;&#29992;&#30452;&#25509;&#21021;&#22987;&#21270;&#35821;&#27861; <span class="t-v">(1)</span>&#65288;&#24102;&#22278;&#25324;&#21495;&#65289;&#30340;&#21464;&#37327;&#22768;&#26126;&#21644;<a href="cpp-language-function.html">&#20989;&#25968;&#22768;&#26126;</a>&#20043;&#38388;&#26377;&#27495;&#20041;&#30340;&#24773;&#20917;&#19979;&#65292;&#32534;&#35793;&#22120;&#22987;&#32456;&#36873;&#25321;&#20989;&#25968;&#22768;&#26126;&#12290;&#27492;&#28040;&#27495;&#20041;&#35268;&#21017;&#26377;&#26102;&#26159;&#21453;&#30452;&#35273;&#30340;&#65292;&#24182;&#19988;&#24050;&#34987;&#31216;&#20026;<a href="https://en.wikipedia.org/wiki/Most_vexing_parse" class="extiw" title="enwiki:Most vexing parse">&#26368;&#28902;&#20154;&#30340;&#20998;&#26512;</a>&#12290;</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;">
<div class="cpp source-cpp">
<pre class="de1"><span class="co2">#include &lt;iterator&gt;</span>
<span class="co2">#include &lt;string&gt;</span>
<span class="co2">#include &lt;fstream&gt;</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
<a href="cpp-io-basic_ifstream.html"><span class="kw1732">std::<span class="me2">ifstream</span></span></a> file<span class="br0">(</span><span class="st0">&quot;data.txt&quot;</span><span class="br0">)</span><span class="sy4">;</span>
<span class="co1">// &#19979;&#38754;&#26159;&#20989;&#25968;&#22768;&#26126;&#65306;</span>
<a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a> str<span class="br0">(</span><a href="cpp-iterator-istreambuf_iterator.html"><span class="kw669">std::<span class="me2">istreambuf_iterator</span></span></a><span class="sy1">&lt;</span><span class="kw4">char</span><span class="sy1">&gt;</span><span class="br0">(</span>file<span class="br0">)</span>,
<a href="cpp-iterator-istreambuf_iterator.html"><span class="kw669">std::<span class="me2">istreambuf_iterator</span></span></a><span class="sy1">&lt;</span><span class="kw4">char</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<span class="co1">// &#23427;&#22768;&#26126;&#21517;&#20026; str &#30340;&#20989;&#25968;&#65292;&#20854;&#36820;&#22238;&#31867;&#22411;&#20026; std::string&#65292;</span>
<span class="co1">// &#31532;&#19968;&#21442;&#25968;&#25317;&#26377; std::istreambuf_iterator&lt;char&gt; &#31867;&#22411;&#21644;&#21517;&#31216; &quot;file&quot;</span>
<span class="co1">// &#31532;&#20108;&#21442;&#25968;&#26080;&#21517;&#31216;&#24182;&#25317;&#26377;&#31867;&#22411; std::istreambuf_iterator&lt;char&gt;()&#65292;</span>
<span class="co1">// &#23427;&#34987;&#37325;&#20889;&#25104;&#20989;&#25968;&#25351;&#38024;&#31867;&#22411; std::istreambuf_iterator&lt;char&gt;(*)()</span>
<span class="co1">// C++11 &#21069;&#30340;&#20462;&#27491;&#65306;&#29992;&#39069;&#22806;&#25324;&#21495;&#29615;&#32469;&#20854;&#20013;&#19968;&#20010;&#23454;&#21442;</span>
<a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a> str<span class="br0">(</span> <span class="br0">(</span><a href="cpp-iterator-istreambuf_iterator.html"><span class="kw669">std::<span class="me2">istreambuf_iterator</span></span></a><span class="sy1">&lt;</span><span class="kw4">char</span><span class="sy1">&gt;</span><span class="br0">(</span>file<span class="br0">)</span> <span class="br0">)</span>,
<a href="cpp-iterator-istreambuf_iterator.html"><span class="kw669">std::<span class="me2">istreambuf_iterator</span></span></a><span class="sy1">&lt;</span><span class="kw4">char</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<span class="co1">// C++11 &#21518;&#30340;&#20462;&#27491;&#65306;&#21015;&#34920;&#21021;&#22987;&#21270;&#20219;&#24847;&#23454;&#21442;</span>
<a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a> str<span class="br0">(</span><a href="cpp-iterator-istreambuf_iterator.html"><span class="kw669">std::<span class="me2">istreambuf_iterator</span></span></a><span class="sy1">&lt;</span><span class="kw4">char</span><span class="sy1">&gt;</span><span class="br0">{</span>file<span class="br0">}</span>, <span class="br0">{</span><span class="br0">}</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div>
</div>
<p>&#31867;&#20284;&#22320;&#65292;&#22312;&#20197;&#20989;&#25968;&#24335;&#36716;&#22411;&#34920;&#36798;&#24335; <span class="t-v">(3)</span> &#20026;&#20854;&#26368;&#24038;&#23376;&#34920;&#36798;&#24335;&#30340;&#34920;&#36798;&#24335;&#35821;&#21477;&#65292;&#21644;&#22768;&#26126;&#35821;&#21477;&#38388;&#26377;&#27495;&#20041;&#30340;&#24773;&#20917;&#19979;&#65292;&#20197;&#23558;&#23427;&#24403;&#20570;&#22768;&#26126;&#35299;&#20915;&#27495;&#20041;&#12290;&#27492;&#28040;&#27495;&#20041;&#26159;&#32431;&#35821;&#27861;&#30340;&#65306;&#23427;&#19981;&#32771;&#34385;&#35821;&#21477;&#20013;&#20986;&#29616;&#30340;&#21517;&#23383;&#38500;&#20102;&#26159;&#21542;&#20026;&#31867;&#22411;&#21517;&#20043;&#22806;&#30340;&#21547;&#20041;&#12290;</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;">
<div class="cpp source-cpp">
<pre class="de1"><span class="kw1">struct</span> M <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
<span class="kw1">struct</span> L <span class="br0">{</span> L<span class="br0">(</span>M<span class="sy3">&amp;</span><span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span><span class="sy4">;</span>
M n<span class="sy4">;</span>
<span class="kw4">void</span> f<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
M<span class="br0">(</span>m<span class="br0">)</span><span class="sy4">;</span> <span class="co1">// &#22768;&#26126;&#65292;&#31561;&#20215;&#20110; M m;</span>
L<span class="br0">(</span>n<span class="br0">)</span><span class="sy4">;</span> <span class="co1">// &#38750;&#33391;&#26500;&#30340;&#22768;&#26126;</span>
L<span class="br0">(</span>l<span class="br0">)</span><span class="br0">(</span>m<span class="br0">)</span><span class="sy4">;</span> <span class="co1">// &#20173;&#28982;&#26159;&#22768;&#26126;</span>
<span class="br0">}</span></pre></div>
</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;string&gt;</span>
<span class="co2">#include &lt;iostream&gt;</span>
<span class="co2">#include &lt;memory&gt;</span>
<span class="kw1">struct</span> Foo <span class="br0">{</span>
<span class="kw4">int</span> mem<span class="sy4">;</span>
<span class="kw1">explicit</span> Foo<span class="br0">(</span><span class="kw4">int</span> n<span class="br0">)</span> <span class="sy4">:</span> mem<span class="br0">(</span>n<span class="br0">)</span> <span class="br0">{</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>
<a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a> s1<span class="br0">(</span><span class="st0">&quot;test&quot;</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// &#33258; const char* &#30340;&#26500;&#36896;&#20989;&#25968;</span>
<a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a> s2<span class="br0">(</span><span class="nu0">10</span>, <span class="st0">&#39;a&#39;</span><span class="br0">)</span><span class="sy4">;</span>
<a href="cpp-memory-unique_ptr.html"><span class="kw733">std::<span class="me2">unique_ptr</span></span></a><span class="sy1">&lt;</span><span class="kw4">int</span><span class="sy1">&gt;</span> p<span class="br0">(</span>new <span class="kw4">int</span><span class="br0">(</span><span class="nu0">1</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// OK&#65306;&#20801;&#35768; explicit &#26500;&#36896;&#20989;&#25968;</span>
<span class="co1">// std::unique_ptr&lt;int&gt; p = new int(1); // &#38169;&#35823;&#65306;&#26500;&#36896;&#20989;&#25968;&#20026; explicit</span>
Foo f<span class="br0">(</span><span class="nu0">2</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// f &#34987;&#30452;&#25509;&#21021;&#22987;&#21270;&#65306;</span>
<span class="co1">// &#26500;&#36896;&#20989;&#25968;&#24418;&#21442; n &#20174;&#21491;&#20540; 2 &#22797;&#21046;&#21021;&#22987;&#21270;</span>
<span class="co1">// f.mem &#20174;&#24418;&#21442; n &#30452;&#25509;&#21021;&#22987;&#21270;</span>
<span class="co1">// Foo f2 = 2; // &#38169;&#35823;&#65306;&#26500;&#36896;&#20989;&#25968;&#20026; explicit</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> s1 <span class="sy1">&lt;&lt;</span> <span class="st0">&#39; &#39;</span> <span class="sy1">&lt;&lt;</span> s2 <span class="sy1">&lt;&lt;</span> <span class="st0">&#39; &#39;</span> <span class="sy1">&lt;&lt;</span> <span class="sy2">*</span>p <span class="sy1">&lt;&lt;</span> <span class="st0">&#39; &#39;</span> <span class="sy1">&lt;&lt;</span> f.<span class="me1">mem</span> <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>
</div>
<p>&#36755;&#20986;&#65306;</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;">
<div class="text source-text">
<pre class="de1">test aaaaaaaaaa 1 2</pre></div>
</div>
</div>
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