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</table></div><div><span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/navbar_content&action=edit">[edit]</a></span></div></div></div></div><div class="t-navbar-sep"> </div><div class="t-navbar-head"><a href="../container.html" title="cpp/container"> Containers library</a><div class="t-navbar-menu"><div><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="array.html" title="cpp/container/array"><span class="t-lines"><span>array</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></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="vector.html" title="cpp/container/vector"><span class="t-lines"><span>vector</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="deque.html" title="cpp/container/deque"><span class="t-lines"><span>deque</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="forward_list.html" title="cpp/container/forward list"><span class="t-lines"><span>forward_list</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></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="list.html" title="cpp/container/list"><span class="t-lines"><span>list</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="set.html" title="cpp/container/set"><span class="t-lines"><span>set</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="multiset.html" title="cpp/container/multiset"><span class="t-lines"><span>multiset</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="map.html" title="cpp/container/map"><span class="t-lines"><span>map</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="multimap.html" title="cpp/container/multimap"><span class="t-lines"><span>multimap</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_set.html" title="cpp/container/unordered set"><span class="t-lines"><span>unordered_set</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></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_multiset.html" title="cpp/container/unordered multiset"><span class="t-lines"><span>unordered_multiset</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></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><strong class="selflink"><span class="t-lines"><span>unordered_map</span></span></strong></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_multimap.html" title="cpp/container/unordered multimap"><span class="t-lines"><span>unordered_multimap</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></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="stack.html" title="cpp/container/stack"><span class="t-lines"><span>stack</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="queue.html" title="cpp/container/queue"><span class="t-lines"><span>queue</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="priority_queue.html" title="cpp/container/priority queue"><span class="t-lines"><span>priority_queue</span></span></a></div></div></td></tr>
</table></div><div><span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/navbar_content&action=edit">[edit]</a></span></div></div></div></div><div class="t-navbar-sep"> </div><div class="t-navbar-head"><strong class="selflink"><tt>std::unordered_map</tt></strong><div class="t-navbar-menu"><div><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv-h1"><td colspan="5"> Member functions</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/unordered_map.html" title="cpp/container/unordered map/unordered map"><span class="t-lines"><span>unordered_map::unordered_map</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/~unordered_map.html" title="cpp/container/unordered map/~unordered map"><span class="t-lines"><span>unordered_map::~unordered_map</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/operator=.html" title="cpp/container/unordered map/operator="><span class="t-lines"><span>unordered_map::operator=</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/get_allocator.html" title="cpp/container/unordered map/get allocator"><span class="t-lines"><span>unordered_map::get_allocator</span></span></a></div></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Iterators</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/begin.html" title="cpp/container/unordered map/begin"><span class="t-lines"><span>unordered_map::begin</span><span>unordered_map::cbegin</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/end.html" title="cpp/container/unordered map/end"><span class="t-lines"><span>unordered_map::end</span><span>unordered_map::cend</span></span></a></div></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Capacity</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/erase.html" title="cpp/container/unordered map/erase"><span class="t-lines"><span>unordered_map::erase</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/size.html" title="cpp/container/unordered map/size"><span class="t-lines"><span>unordered_map::size</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/max_size.html" title="cpp/container/unordered map/max size"><span class="t-lines"><span>unordered_map::max_size</span></span></a></div></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Modifiers</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/clear.html" title="cpp/container/unordered map/clear"><span class="t-lines"><span>unordered_map::clear</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/insert.html" title="cpp/container/unordered map/insert"><span class="t-lines"><span>unordered_map::insert</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/insert_or_assign.html" title="cpp/container/unordered map/insert or assign"><span class="t-lines"><span>unordered_map::insert_or_assign</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/emplace.html" title="cpp/container/unordered map/emplace"><span class="t-lines"><span>unordered_map::emplace</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/emplace_hint.html" title="cpp/container/unordered map/emplace hint"><span class="t-lines"><span>unordered_map::emplace_hint</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/try_emplace.html" title="cpp/container/unordered map/try emplace"><span class="t-lines"><span>unordered_map::try_emplace</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/erase.html" title="cpp/container/unordered map/erase"><span class="t-lines"><span>unordered_map::erase</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/swap.html" title="cpp/container/unordered map/swap"><span class="t-lines"><span>unordered_map::swap</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/extract.html" title="cpp/container/unordered map/extract"><span class="t-lines"><span>unordered_map::extract</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/merge.html" title="cpp/container/unordered map/merge"><span class="t-lines"><span>unordered_map::merge</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Lookup</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/count.html" title="cpp/container/unordered map/count"><span class="t-lines"><span>unordered_map::count</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/find.html" title="cpp/container/unordered map/find"><span class="t-lines"><span>unordered_map::find</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/equal_range.html" title="cpp/container/unordered map/equal range"><span class="t-lines"><span>unordered_map::equal_range</span></span></a></div></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Bucket interface</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/begin2.html" title="cpp/container/unordered map/begin2"><span class="t-lines"><span>unordered_map::begin2</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/end2.html" title="cpp/container/unordered map/end2"><span class="t-lines"><span>unordered_map::end2</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/bucket_count.html" title="cpp/container/unordered map/bucket count"><span class="t-lines"><span>unordered_map::bucket_count</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/max_bucket_count.html" title="cpp/container/unordered map/max bucket count"><span class="t-lines"><span>unordered_map::max_bucket_count</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/bucket_size.html" title="cpp/container/unordered map/bucket size"><span class="t-lines"><span>unordered_map::bucket_size</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/bucket.html" title="cpp/container/unordered map/bucket"><span class="t-lines"><span>unordered_map::bucket</span></span></a></div></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Hash policy</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/load_factor.html" title="cpp/container/unordered map/load factor"><span class="t-lines"><span>unordered_map::load_factor</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/max_load_factor.html" title="cpp/container/unordered map/max load factor"><span class="t-lines"><span>unordered_map::max_load_factor</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/rehash.html" title="cpp/container/unordered map/rehash"><span class="t-lines"><span>unordered_map::rehash</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/reserve.html" title="cpp/container/unordered map/reserve"><span class="t-lines"><span>unordered_map::reserve</span></span></a></div></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Observers</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/hash_function.html" title="cpp/container/unordered map/hash function"><span class="t-lines"><span>unordered_map::hash_function</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unordered_map/key_eq.html" title="cpp/container/unordered map/key eq"><span class="t-lines"><span>unordered_map::key_eq</span></span></a></div></div></td></tr>
</table></div><div><span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/unordered_map/navbar_content&action=edit">[edit]</a></span></div></div></div></div><div class="t-navbar-sep"> </div></div>
<table class="t-dcl-begin"><tbody>
<tr class="t-dsc-header">
<td> <div>Defined in header <code><a href="../header/unordered_map.html" title="cpp/header/unordered map"><unordered_map></a></code>
</div></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl t-since-cxx11">
<td> <div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span><br />
<p>    <span class="kw1">class</span> Key,<br />
    <span class="kw1">class</span> T,<br />
    <span class="kw1">class</span> Hash <span class="sy1">=</span> <a href="../utility/hash.html"><span class="kw1121">std::<span class="me2">hash</span></span></a><span class="sy1"><</span>Key<span class="sy1">></span>,<br />
    <span class="kw1">class</span> KeyEqual <span class="sy1">=</span> <a href="../utility/functional/equal_to.html"><span class="kw1035">std::<span class="me2">equal_to</span></span></a><span class="sy1"><</span>Key<span class="sy1">></span>,<br />
    <span class="kw1">class</span> Allocator <span class="sy1">=</span> <a href="../memory/allocator.html"><span class="kw700">std::<span class="me2">allocator</span></span></a><span class="sy1"><</span> <a href="../utility/pair.html"><span class="kw1096">std::<span class="me2">pair</span></span></a><span class="sy1"><</span><span class="kw4">const</span> Key, T<span class="sy1">></span> <span class="sy1">></span><br />
</p>
<span class="sy1">></span> <span class="kw1">class</span> unordered_map<span class="sy4">;</span></span></div></td>
<td> (1) </td>
<td> <span class="t-mark-rev t-since-cxx11">(since C++11)</span> </td>
</tr>
<tr class="t-dcl t-since-cxx17">
<td> <div><span class="mw-geshi cpp source-cpp"><span class="kw1">namespace</span> pmr <span class="br0">{</span><br />
<p>    <span class="kw1">template</span> <span class="sy1"><</span><span class="kw1">class</span> Key, <span class="kw1">class</span> T,<br />
              <span class="kw1">class</span> Hash <span class="sy1">=</span> <a href="../utility/hash.html"><span class="kw1121">std::<span class="me2">hash</span></span></a><span class="sy1"><</span>Key<span class="sy1">></span>,<br />
              <span class="kw1">class</span> Pred <span class="sy1">=</span> <a href="../utility/functional/equal_to.html"><span class="kw1035">std::<span class="me2">equal_to</span></span></a><span class="sy1"><</span>Key<span class="sy1">>></span><br />
    <span class="kw1">using</span> unordered_map <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">unordered_map</span><span class="sy1"><</span>Key, T, Hash, Pred,<br />
                              <a href="../memory/polymorphic_allocator.html"><span class="kw707">std::<span class="me2">pmr</span><span class="sy4">::</span><span class="me2">polymorphic_allocator</span></span></a><span class="sy1"><</span><a href="../utility/pair.html"><span class="kw1096">std::<span class="me2">pair</span></span></a><span class="sy1"><</span><span class="kw4">const</span> Key,T<span class="sy1">>>></span><span class="sy4">;</span><br />
</p>
<span class="br0">}</span></span></div></td>
<td> (2) </td>
<td> <span class="t-mark-rev t-since-cxx17">(since C++17)</span> </td>
</tr>
<tr class="t-dcl-sep"><td></td><td></td><td></td></tr>
</tbody></table>
<p>Unordered map is an associative container that contains key-value pairs with unique keys. Search, insertion, and removal of elements have average constant-time complexity.
</p><p>Internally, the elements are not sorted in any particular order, but organized into buckets. Which bucket an element is placed into depends entirely on the hash of its key. This allows fast access to individual elements, since once the hash is computed, it refers to the exact bucket the element is placed into.
</p><p><code>std::unordered_map</code> meets the requirements of <a href="../concept/Container.html" title="cpp/concept/Container"><code>Container</code></a>, <a href="../concept/AllocatorAwareContainer.html" title="cpp/concept/AllocatorAwareContainer"><code>AllocatorAwareContainer</code></a>, <a href="../concept/UnorderedAssociativeContainer.html" title="cpp/concept/UnorderedAssociativeContainer"><code>UnorderedAssociativeContainer</code></a>.
</p>
<table id="toc" class="toc"><tr><td><div id="toctitle"><h2>Contents</h2></div>
<ul>
<li class="toclevel-1 tocsection-1"><a href="unordered_map.html#Iterator_invalidation"><span class="tocnumber">1</span> <span class="toctext">Iterator invalidation</span></a>
<ul>
<li class="toclevel-2 tocsection-2"><a href="unordered_map.html#Notes"><span class="tocnumber">1.1</span> <span class="toctext">Notes</span></a></li>
</ul>
</li>
<li class="toclevel-1 tocsection-3"><a href="unordered_map.html#Member_types"><span class="tocnumber">2</span> <span class="toctext">Member types</span></a></li>
<li class="toclevel-1 tocsection-4"><a href="unordered_map.html#Member_functions"><span class="tocnumber">3</span> <span class="toctext">Member functions</span></a>
<ul>
<li class="toclevel-2"><a href="unordered_map.html#Iterators"><span class="tocnumber">3.1</span> <span class="toctext">Iterators</span></a></li>
<li class="toclevel-2"><a href="unordered_map.html#Capacity"><span class="tocnumber">3.2</span> <span class="toctext">Capacity</span></a></li>
<li class="toclevel-2"><a href="unordered_map.html#Modifiers"><span class="tocnumber">3.3</span> <span class="toctext">Modifiers</span></a></li>
<li class="toclevel-2"><a href="unordered_map.html#Lookup"><span class="tocnumber">3.4</span> <span class="toctext">Lookup</span></a></li>
<li class="toclevel-2"><a href="unordered_map.html#Bucket_interface"><span class="tocnumber">3.5</span> <span class="toctext">Bucket interface</span></a></li>
<li class="toclevel-2"><a href="unordered_map.html#Hash_policy"><span class="tocnumber">3.6</span> <span class="toctext">Hash policy</span></a></li>
<li class="toclevel-2"><a href="unordered_map.html#Observers"><span class="tocnumber">3.7</span> <span class="toctext">Observers</span></a></li>
</ul>
</li>
<li class="toclevel-1 tocsection-5"><a href="unordered_map.html#Non-member_functions"><span class="tocnumber">4</span> <span class="toctext">Non-member functions</span></a></li>
<li class="toclevel-1 tocsection-6"><a href="unordered_map.html#Example"><span class="tocnumber">5</span> <span class="toctext">Example</span></a></li>
</ul>
</td></tr></table>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/container/unordered_map&action=edit&section=1" title="Edit section: Iterator invalidation">edit</a>]</span> <span class="mw-headline" id="Iterator_invalidation">Iterator invalidation</span></h3>
<table class="dsctable" style="font-size:0.8em">
<tr>
<th> Operations
</th>
<th> Invalidated
</th></tr>
<tr>
<td> All read only operations, <span class="t-lc"><a href="unordered_map/swap.html" title="cpp/container/unordered map/swap">swap</a></span>, <span class="t-lc"><a href="../algorithm/swap.html" title="cpp/algorithm/swap">std::swap</a></span>
</td>
<td> Never
</td></tr>
<tr>
<td> <span class="t-lc"><a href="unordered_map/clear.html" title="cpp/container/unordered map/clear">clear</a></span>, <span class="t-lc"><a href="unordered_map/rehash.html" title="cpp/container/unordered map/rehash">rehash</a></span>, <span class="t-lc"><a href="unordered_map/reserve.html" title="cpp/container/unordered map/reserve">reserve</a></span>, <span class="t-lc"><a href="unordered_map/operator=.html" title="cpp/container/unordered map/operator=">operator=</a></span>
</td>
<td> Always
</td></tr>
<tr>
<td> <span class="t-lc"><a href="unordered_map/insert.html" title="cpp/container/unordered map/insert">insert</a></span>, <span class="t-lc"><a href="unordered_map/emplace.html" title="cpp/container/unordered map/emplace">emplace</a></span>, <span class="t-lc"><a href="unordered_map/emplace_hint.html" title="cpp/container/unordered map/emplace hint">emplace_hint</a></span>, <span class="t-lc"><a href="unordered_map/operator_at.html" title="cpp/container/unordered map/operator at">operator[]</a></span>
</td>
<td> Only if causes rehash
</td></tr>
<tr>
<td> <span class="t-lc"><a href="unordered_map/erase.html" title="cpp/container/unordered map/erase">erase</a></span>
</td>
<td> Only to the element erased
</td></tr></table>
<h4><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/container/unordered_map&action=edit&section=2" title="Edit section: Notes">edit</a>]</span> <span class="mw-headline" id="Notes">Notes</span></h4>
<ul><li> The swap functions do not invalidate any of the iterators inside the container, but they do invalidate the iterator marking the end of the swap region.
</li></ul>
<ul><li> References and pointers to either key or data stored in the container are only invalidated by erasing that element, even when the corresponding iterator is invalidated.
</li></ul>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/container/unordered_map&action=edit&section=3" title="Edit section: Member types">edit</a>]</span> <span class="mw-headline" id="Member_types">Member types</span></h3>
<table class="t-dsc-begin">
<tr class="t-dsc-hitem">
<td> Member type
</td>
<td> Definition
</td></tr>
<tr class="t-dsc">
<td> <code>key_type</code>
</td>
<td> <code>Key</code> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_key_type&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>mapped_type</code>
</td>
<td> <code>T</code> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_mapped_type&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>value_type</code>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="../utility/pair.html"><span class="kw1096">std::<span class="me2">pair</span></span></a><span class="sy1"><</span><span class="kw4">const</span> Key, T<span class="sy1">></span></span></span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_value_type&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>size_type</code>
</td>
<td> Unsigned integer type (usually <span class="t-lc"><a href="../types/size_t.html" title="cpp/types/size t">std::size_t</a></span>) <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_size_type&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>difference_type</code>
</td>
<td> Signed integer type (usually <span class="t-lc"><a href="../types/ptrdiff_t.html" title="cpp/types/ptrdiff t">std::ptrdiff_t</a></span>) <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_difference_type&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>hasher</code>
</td>
<td> <code>Hash</code> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_hasher&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>key_equal</code>
</td>
<td> <code>KeyEqual</code> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_key_equal&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>allocator_type</code>
</td>
<td> <code>Allocator</code> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_allocator_type&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>reference</code>
</td>
<td> <code>value_type&</code> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_reference&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>const_reference</code>
</td>
<td> <code>const value_type&</code> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_const_reference&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>pointer</code>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="../memory/allocator_traits.html"><span class="kw701">std::<span class="me2">allocator_traits</span></span></a><span class="sy1"><</span>Allocator<span class="sy1">></span><span class="sy4">::</span><span class="me2">pointer</span></span></span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_pointer&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>const_pointer</code>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="../memory/allocator_traits.html"><span class="kw701">std::<span class="me2">allocator_traits</span></span></a><span class="sy1"><</span>Allocator<span class="sy1">></span><span class="sy4">::</span><span class="me2">const_pointer</span></span></span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_const_pointer&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>iterator</code>
</td>
<td> <a href="../concept/ForwardIterator.html" title="cpp/concept/ForwardIterator"><code>ForwardIterator</code></a> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_iterator&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>const_iterator</code>
</td>
<td> Constant forward iterator <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_const_iterator&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>local_iterator</code>
</td>
<td> An iterator type whose category, value, difference, pointer and<br /> reference types are the same as <code>iterator</code>. This iterator<br /> can be used to iterate through a single bucket but not across buckets<span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_local_iterator&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>const_local_iterator</code>
</td>
<td> An iterator type whose category, value, difference, pointer and<br /> reference types are the same as <code>const_iterator</code>. This iterator<br /> can be used to iterate through a single bucket but not across buckets<span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_const_local_iterator&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>node_type</code>
</td>
<td> a specialization of <a href="node_handle.html" title="cpp/container/node handle">node handle</a> representing a container node <span class="t-mark-rev t-since-cxx17">(since C++17)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_node_type&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <code>insert_return_type</code>
</td>
<td> type describing the result of inserting a <code>node_type</code>, a specialization of <div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">template</span> <span class="sy1"><</span><span class="kw1">class</span> Iterator, <span class="kw1">class</span> NodeType<span class="sy1">></span> <span class="kw1">struct</span> <span class="coMULTI">/*unspecified*/</span> <span class="br0">{</span>
Iterator position<span class="sy4">;</span>
<span class="kw4">bool</span> inserted<span class="sy4">;</span>
NodeType node<span class="sy4">;</span>
<span class="br0">}</span><span class="sy4">;</span></pre></div></div> instantiated with template arguments <code>iterator</code> and <code>node_type</code>. <span class="t-mark-rev t-since-cxx17">(since C++17)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_insert_return_type&action=edit">[edit]</a></span>
</td></tr>
</table>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/container/unordered_map&action=edit&section=4" title="Edit section: Member functions">edit</a>]</span> <span class="mw-headline" id="Member_functions">Member functions</span></h3>
<table class="t-dsc-begin">
<tr class="t-dsc">
<td> <div class="t-dsc-member-div t-dsc-member-nobold-div"><div><a href="unordered_map/unordered_map.html" title="cpp/container/unordered map/unordered map"> <span class="t-lines"><span>(constructor)</span></span></a></div></div>
</td>
<td> constructs the <code>unordered_map</code> <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_constructor&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div t-dsc-member-nobold-div"><div><a href="unordered_map/~unordered_map.html" title="cpp/container/unordered map/~unordered map"> <span class="t-lines"><span>(destructor)</span></span></a></div></div>
</td>
<td> destructs the <code>unordered_map</code> <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_destructor&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/operator=.html" title="cpp/container/unordered map/operator="> <span class="t-lines"><span>operator=</span></span></a></div></div>
</td>
<td> assigns values to the container <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_operator%3D&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/get_allocator.html" title="cpp/container/unordered map/get allocator"> <span class="t-lines"><span>get_allocator</span></span></a></div></div>
</td>
<td> returns the associated allocator <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_get_allocator&action=edit">[edit]</a></span>
</td></tr>
<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Iterators"> Iterators </span></h5>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/begin.html" title="cpp/container/unordered map/begin"> <span class="t-lines"><span>begin</span><span> cbegin</span></span></a></div><div><span class="t-lines"><span></span><span></span></span></div></div>
</td>
<td> returns an iterator to the beginning <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_begin&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/end.html" title="cpp/container/unordered map/end"> <span class="t-lines"><span>end </span><span>cend</span></span></a></div><div><span class="t-lines"><span></span><span></span></span></div></div>
</td>
<td> returns an iterator to the end <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_end&action=edit">[edit]</a></span>
</td></tr>
<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Capacity"> Capacity </span></h5>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/empty.html" title="cpp/container/unordered map/empty"> <span class="t-lines"><span>empty</span></span></a></div></div>
</td>
<td> checks whether the container is empty <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_empty&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/size.html" title="cpp/container/unordered map/size"> <span class="t-lines"><span>size</span></span></a></div></div>
</td>
<td> returns the number of elements <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_size&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/max_size.html" title="cpp/container/unordered map/max size"> <span class="t-lines"><span>max_size</span></span></a></div></div>
</td>
<td> returns the maximum possible number of elements <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_max_size&action=edit">[edit]</a></span>
</td></tr>
<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Modifiers"> Modifiers </span></h5>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/clear.html" title="cpp/container/unordered map/clear"> <span class="t-lines"><span>clear</span></span></a></div></div>
</td>
<td> clears the contents <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_clear&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/insert.html" title="cpp/container/unordered map/insert"> <span class="t-lines"><span>insert</span></span></a></div></div>
</td>
<td> inserts elements <span class="t-rev-inl t-since-cxx17"><span>or nodes</span> <span><span class="t-mark-rev t-since-cxx17">(since C++17)</span></span></span> <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_insert&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/insert_or_assign.html" title="cpp/container/unordered map/insert or assign"> <span class="t-lines"><span>insert_or_assign</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div>
</td>
<td> inserts an element or assigns to the current element if the key already exists <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_insert_or_assign&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/emplace.html" title="cpp/container/unordered map/emplace"> <span class="t-lines"><span>emplace</span></span></a></div></div>
</td>
<td> constructs element in-place <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_emplace&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/emplace_hint.html" title="cpp/container/unordered map/emplace hint"> <span class="t-lines"><span>emplace_hint</span></span></a></div></div>
</td>
<td> constructs elements in-place using a hint <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_emplace_hint&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/try_emplace.html" title="cpp/container/unordered map/try emplace"> <span class="t-lines"><span>try_emplace</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div>
</td>
<td> inserts in-place if the key does not exist, does nothing if the key exists <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_try_emplace&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/erase.html" title="cpp/container/unordered map/erase"> <span class="t-lines"><span>erase</span></span></a></div></div>
</td>
<td> erases elements <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_erase&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/swap.html" title="cpp/container/unordered map/swap"> <span class="t-lines"><span>swap</span></span></a></div></div>
</td>
<td> swaps the contents <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_swap&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/extract.html" title="cpp/container/unordered map/extract"> <span class="t-lines"><span>extract</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div>
</td>
<td> extracts nodes from the container <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_extract&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/merge.html" title="cpp/container/unordered map/merge"> <span class="t-lines"><span>merge</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div>
</td>
<td> splices nodes from another container <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_merge&action=edit">[edit]</a></span>
</td></tr>
<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Lookup"> Lookup </span></h5>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/at.html" title="cpp/container/unordered map/at"> <span class="t-lines"><span>at</span></span></a></div></div>
</td>
<td> access specified element with bounds checking <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_at&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/operator_at.html" title="cpp/container/unordered map/operator at"> <span class="t-lines"><span>operator[]</span></span></a></div></div>
</td>
<td> access specified element <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_operator_at&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/count.html" title="cpp/container/unordered map/count"> <span class="t-lines"><span>count</span></span></a></div></div>
</td>
<td> returns the number of elements matching specific key <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_count&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/find.html" title="cpp/container/unordered map/find"> <span class="t-lines"><span>find</span></span></a></div></div>
</td>
<td> finds element with specific key <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_find&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/equal_range.html" title="cpp/container/unordered map/equal range"> <span class="t-lines"><span>equal_range</span></span></a></div></div>
</td>
<td> returns range of elements matching a specific key <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_equal_range&action=edit">[edit]</a></span>
</td></tr>
<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Bucket_interface"> Bucket interface </span></h5>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/begin2.html" title="cpp/container/unordered map/begin2"> <span class="t-lines"><span>begin<span class="t-dsc-small">(int)</span></span><span> cbegin<span class="t-dsc-small">(int)</span></span></span></a></div></div>
</td>
<td> returns an iterator to the beginning of the specified bucket <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_begin(int)&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/end2.html" title="cpp/container/unordered map/end2"> <span class="t-lines"><span>end<span class="t-dsc-small">(int)</span></span><span> cend<span class="t-dsc-small">(int)</span></span></span></a></div></div>
</td>
<td> returns an iterator to the end of the specified bucket <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_end(int)&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/bucket_count.html" title="cpp/container/unordered map/bucket count"> <span class="t-lines"><span>bucket_count</span></span></a></div></div>
</td>
<td> returns the number of buckets <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_bucket_count&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/max_bucket_count.html" title="cpp/container/unordered map/max bucket count"> <span class="t-lines"><span>max_bucket_count</span></span></a></div></div>
</td>
<td> returns the maximum number of buckets <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_max_bucket_count&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/bucket_size.html" title="cpp/container/unordered map/bucket size"> <span class="t-lines"><span>bucket_size</span></span></a></div></div>
</td>
<td> returns the number of elements in specific bucket <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_bucket_size&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/bucket.html" title="cpp/container/unordered map/bucket"> <span class="t-lines"><span>bucket</span></span></a></div></div>
</td>
<td> returns the bucket for specific key <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_bucket&action=edit">[edit]</a></span>
</td></tr>
<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Hash_policy"> Hash policy </span></h5>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/load_factor.html" title="cpp/container/unordered map/load factor"> <span class="t-lines"><span>load_factor</span></span></a></div></div>
</td>
<td> returns average number of elements per bucket <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_load_factor&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/max_load_factor.html" title="cpp/container/unordered map/max load factor"> <span class="t-lines"><span>max_load_factor</span></span></a></div></div>
</td>
<td> manages maximum average number of elements per bucket <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_max_load_factor&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/rehash.html" title="cpp/container/unordered map/rehash"> <span class="t-lines"><span>rehash</span></span></a></div></div>
</td>
<td> reserves at least the specified number of buckets.<br />This regenerates the hash table. <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_rehash&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/reserve.html" title="cpp/container/unordered map/reserve"> <span class="t-lines"><span>reserve</span></span></a></div></div>
</td>
<td> reserves space for at least the specified number of elements.<br />This regenerates the hash table. <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_reserve&action=edit">[edit]</a></span>
</td></tr>
<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Observers"> Observers </span></h5>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/hash_function.html" title="cpp/container/unordered map/hash function"> <span class="t-lines"><span>hash_function</span></span></a></div></div>
</td>
<td> returns function used to hash the keys <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_hash_function&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/key_eq.html" title="cpp/container/unordered map/key eq"> <span class="t-lines"><span>key_eq</span></span></a></div></div>
</td>
<td> returns the function used to compare keys for equality <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_key_eq&action=edit">[edit]</a></span>
</td></tr>
</table>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/container/unordered_map&action=edit&section=5" title="Edit section: Non-member functions">edit</a>]</span> <span class="mw-headline" id="Non-member_functions">Non-member functions</span></h3>
<table class="t-dsc-begin">
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/operator_cmp.html" title="cpp/container/unordered map/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td> compares the values in the unordered_map <br /> <span class="t-mark">(function template)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_operator_cmp_unord&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="unordered_map/swap2.html" title="cpp/container/unordered map/swap2"> <span class="t-lines"><span>std::swap<span class="t-dsc-small">(std::unordered_map)</span></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> specializes the <span class="t-lc"><a href="../algorithm/swap.html" title="cpp/algorithm/swap">std::swap</a></span> algorithm <br /> <span class="t-mark">(function template)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/container/dsc_swap2&action=edit">[edit]</a></span>
</td></tr>
</table>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/container/unordered_map&action=edit&section=6" title="Edit section: Example">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 <iostream></span>
<span class="co2">#include <string></span>
<span class="co2">#include <unordered_map></span>
 
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
<span class="co1">// Create an unordered_map of three strings (that map to strings)</span>
std<span class="sy4">::</span><span class="me2">unordered_map</span><span class="sy1"><</span><a href="../string/basic_string.html"><span class="kw1227">std::<span class="me2">string</span></span></a>, <a href="../string/basic_string.html"><span class="kw1227">std::<span class="me2">string</span></span></a><span class="sy1">></span> u <span class="sy1">=</span> <span class="br0">{</span>
<span class="br0">{</span><span class="st0">"RED"</span>,<span class="st0">"#FF0000"</span><span class="br0">}</span>,
<span class="br0">{</span><span class="st0">"GREEN"</span>,<span class="st0">"#00FF00"</span><span class="br0">}</span>,
<span class="br0">{</span><span class="st0">"BLUE"</span>,<span class="st0">"#0000FF"</span><span class="br0">}</span>
<span class="br0">}</span><span class="sy4">;</span>
 
<span class="co1">// Iterate and print keys and values of unordered_map</span>
<span class="kw1">for</span><span class="br0">(</span> <span class="kw4">const</span> <span class="kw4">auto</span><span class="sy3">&</span> n <span class="sy4">:</span> u <span class="br0">)</span> <span class="br0">{</span>
<a href="../io/cout.html"><span class="kw1753">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"Key:["</span> <span class="sy1"><<</span> n.<span class="me1">first</span> <span class="sy1"><<</span> <span class="st0">"] Value:["</span> <span class="sy1"><<</span> n.<span class="me1">second</span> <span class="sy1"><<</span> <span class="st0">"]<span class="es1">\n</span>"</span><span class="sy4">;</span>
<span class="br0">}</span>
 
<span class="co1">// Add two new entries to the unordered_map</span>
u<span class="br0">[</span><span class="st0">"BLACK"</span><span class="br0">]</span> <span class="sy1">=</span> <span class="st0">"#000000"</span><span class="sy4">;</span>
u<span class="br0">[</span><span class="st0">"WHITE"</span><span class="br0">]</span> <span class="sy1">=</span> <span class="st0">"#FFFFFF"</span><span class="sy4">;</span>
 
<span class="co1">// Output values by key</span>
<a href="../io/cout.html"><span class="kw1753">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"The HEX of color RED is:["</span> <span class="sy1"><<</span> u<span class="br0">[</span><span class="st0">"RED"</span><span class="br0">]</span> <span class="sy1"><<</span> <span class="st0">"]<span class="es1">\n</span>"</span><span class="sy4">;</span>
<a href="../io/cout.html"><span class="kw1753">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"The HEX of color BLACK is:["</span> <span class="sy1"><<</span> u<span class="br0">[</span><span class="st0">"BLACK"</span><span class="br0">]</span> <span class="sy1"><<</span> <span class="st0">"]<span class="es1">\n</span>"</span><span class="sy4">;</span>
 
<span class="kw1">return</span> <span class="nu0">0</span><span class="sy4">;</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">Key:[RED] Value:[#FF0000]
Key:[BLUE] Value:[#0000FF]
Key:[GREEN] Value:[#00FF00]
The HEX of color RED is:[#FF0000]
The HEX of color BLACK is:[#000000]</pre></div></div>
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