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<td> <div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span> <span class="kw1">class</span>... <span class="me1">Args</span> <span class="sy1">&gt;</span><br>
<a href="../../utility/pair.html"><span class="kw901">std::<span class="me2">pair</span></span></a><span class="sy1">&lt;</span>iterator,<span class="kw4">bool</span><span class="sy1">&gt;</span> emplace<span class="br0">(</span> Args<span class="sy3">&amp;&amp;</span>... <span class="me1">args</span> <span class="br0">)</span><span class="sy4">;</span></span></div>
</td>
<td class="t-dcl-nopad">  </td>
<td> <span class="t-mark-rev t-since-cxx11">(since C++11)</span> </td>
</tr>
<tr class="t-dcl-sep">
<td></td>
<td></td>
<td></td>
</tr>
</tbody></table>
<p>Inserts a new element into the container by constructing it in-place with the given <code>args</code>.
</p>
<p>Careful use of <code>emplace</code> allows the new element to be constructed while avoiding unnecessary copy or move operations.
The constructor of the new element (i.e. <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="../../utility/pair.html"><span class="kw901">std::<span class="me2">pair</span></span></a><span class="sy1">&lt;</span><span class="kw4">const</span> Key, T<span class="sy1">&gt;</span></span></span>) is called with exactly the same arguments as supplied to <code>emplace</code>, forwarded via <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="../../utility/forward.html"><span class="kw913">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>Args<span class="sy1">&gt;</span><span class="br0">(</span>args<span class="br0">)</span>...</span></span>.
</p>
<p>No iterators or references are invalidated.
</p>
<table id="toc" class="toc"><tr><td>
<div id="toctitle"><h2>Contents</h2></div>
<ul>
<li class="toclevel-1"><a href="#Parameters"><span class="tocnumber">1</span> <span class="toctext">Parameters</span></a></li>
<li class="toclevel-1"><a href="#Return_value"><span class="tocnumber">2</span> <span class="toctext">Return value</span></a></li>
<li class="toclevel-1"><a href="#Exceptions"><span class="tocnumber">3</span> <span class="toctext">Exceptions</span></a></li>
<li class="toclevel-1"><a href="#Complexity"><span class="tocnumber">4</span> <span class="toctext">Complexity</span></a></li>
<li class="toclevel-1"><a href="#Example"><span class="tocnumber">5</span> <span class="toctext">Example</span></a></li>
<li class="toclevel-1"><a href="#See_also"><span class="tocnumber">6</span> <span class="toctext">See also</span></a></li>
</ul>
</td></tr></table>
<h3>
<span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php" title="Template:cpp/container/emplace assoc">edit</a>]</span> <span class="mw-headline" id="Parameters">Parameters</span>
</h3>
<table class="t-par-begin">


<tr class="t-par">
<td>  args
</td>
<td> -
</td>
<td>  arguments to forward to the constructor of the element
</td>
</tr>
</table>
<h3>
<span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php" title="Template:cpp/container/emplace assoc">edit</a>]</span> <span class="mw-headline" id="Return_value">Return value</span>
</h3>
<p>Returns a pair consisting of a <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">bool</span></span></span> denoting whether the insertion took place and an iterator to the inserted element, or the already-existing element if no insertion happened.
</p>
<h3>
<span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php" title="Template:cpp/container/emplace assoc">edit</a>]</span> <span class="mw-headline" id="Exceptions">Exceptions</span>
</h3>
<p>If an exception is thrown by any operation, this function has no effect.
</p>
<h3>
<span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php" title="Template:cpp/container/emplace assoc">edit</a>]</span> <span class="mw-headline" id="Complexity">Complexity</span>
</h3>
<p>Logarithmic in the size of the container.
</p>
<h3>
<span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php" title="Template:cpp/container/emplace assoc">edit</a>]</span> <span class="mw-headline" id="Example">Example</span>
</h3>
<div class="t-example">
<div class="t-example-live-link"><div class="coliru-btn coliru-btn-run-init">Run this code</div></div>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="co2">#include &lt;iostream&gt;</span>
<span class="co2">#include &lt;utility&gt;</span>
 
<span class="co2">#include &lt;map&gt;</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
    <a href="../map.html"><span class="kw1073">std::<span class="me2">map</span></span></a><span class="sy1">&lt;</span><a href="../../string/basic_string.html"><span class="kw1045">std::<span class="me2">string</span></span></a>, <a href="../../string/basic_string.html"><span class="kw1045">std::<span class="me2">string</span></span></a><span class="sy1">&gt;</span> m<span class="sy4">;</span>
 
    <span class="co1">// uses pair's move constructor (overload 8)</span>
    m.<span class="me1">emplace</span><span class="br0">(</span><a href="../../utility/pair/make_pair.html"><span class="kw902">std::<span class="me2">make_pair</span></span></a><span class="br0">(</span><a href="../../string/basic_string.html"><span class="kw1045">std::<span class="me2">string</span></span></a><span class="br0">(</span><span class="st0">"a"</span><span class="br0">)</span>, <a href="../../string/basic_string.html"><span class="kw1045">std::<span class="me2">string</span></span></a><span class="br0">(</span><span class="st0">"a"</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// uses pair's converting move constructor (overload 5)</span>
    m.<span class="me1">emplace</span><span class="br0">(</span><a href="../../utility/pair/make_pair.html"><span class="kw902">std::<span class="me2">make_pair</span></span></a><span class="br0">(</span><span class="st0">"b"</span>, <span class="st0">"abcd"</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// uses pair's template constructor (overload 3)</span>
    m.<span class="me1">emplace</span><span class="br0">(</span><span class="st0">"d"</span>, <span class="st0">"ddd"</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// uses pair's piecewise constructor (overload 6)</span>
    m.<span class="me1">emplace</span><span class="br0">(</span><a href="../../utility/piecewise_construct.html"><span class="kw905">std::<span class="me2">piecewise_construct</span></span></a>,
              <a href="../../utility/tuple/forward_as_tuple.html"><span class="kw909">std::<span class="me2">forward_as_tuple</span></span></a><span class="br0">(</span><span class="st0">"c"</span><span class="br0">)</span>,
              <a href="../../utility/tuple/forward_as_tuple.html"><span class="kw909">std::<span class="me2">forward_as_tuple</span></span></a><span class="br0">(</span><span class="nu0">10</span>, <span class="st0">'c'</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">for</span> <span class="br0">(</span><span class="kw4">const</span> <span class="kw4">auto</span> <span class="sy3">&amp;</span>p <span class="sy4">:</span> m<span class="br0">)</span> <span class="br0">{</span>
        <a href="../../io/basic_ostream.html"><span class="kw1439">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> p.<span class="me1">first</span> <span class="sy1">&lt;&lt;</span> <span class="st0">" =&gt; "</span> <span class="sy1">&lt;&lt;</span> p.<span class="me1">second</span> <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
    <span class="br0">}</span>
<span class="br0">}</span></pre></div></div>
<p>Output:
</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="text source-text"><pre class="de1">a =&gt; a
b =&gt; abcd
c =&gt; cccccccccc
d =&gt; ddd</pre></div></div> 
</div>
<h3>
<span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php" title="Template:cpp/container/emplace assoc">edit</a>]</span> <span class="mw-headline" id="See_also">See also</span>
</h3>
<table class="t-dsc-begin">

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div">
<div><a href="emplace_hint.html" title="cpp/container/map/emplace hint"> <span class="t-lines"><span>emplace_hint</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div>
</div>
</td>
<td>   constructs elements in-place using a hint  <br> <span class="t-mark">(public member function)</span> 
</td>
</tr>

<tr class="t-dsc-sep">
<td colspan="2">
</td>
</tr>
<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="insert.html" title="cpp/container/map/insert"> <span class="t-lines"><span>insert</span></span></a></div></div>
</td>
<td>   inserts elements  <br> <span class="t-mark">(public member function)</span> 
</td>
</tr>
</table>

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