std::unordered_multiset

 

C++

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Containers library

array (C++11)

vector

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forward_list (C++11)

list

set

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multimap

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

stack

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std::unordered_multiset

Member functions

unordered_multiset::unordered_multiset

unordered_multiset::~unordered_multiset

unordered_multiset::operator=

unordered_multiset::get_allocator

Iterators

unordered_multiset::beginunordered_multiset::cbegin

unordered_multiset::endunordered_multiset::cend

Capacity

unordered_multiset::erase

unordered_multiset::size

unordered_multiset::max_size

Modifiers

unordered_multiset::clear

unordered_multiset::insert

unordered_multiset::emplace

unordered_multiset::emplace_hint

unordered_multiset::erase

unordered_multiset::swap

Lookup

unordered_multiset::count

unordered_multiset::find

unordered_multiset::equal_range

Bucket interface

unordered_multiset::begin2

unordered_multiset::end2

unordered_multiset::bucket_count

unordered_multiset::max_bucket_count

unordered_multiset::bucket_size

unordered_multiset::bucket

Hash policy

unordered_multiset::load_factor

unordered_multiset::max_load_factor

unordered_multiset::rehash

unordered_multiset::reserve

Observers

unordered_multiset::hash_function

unordered_multiset::key_eq

 

Defined in header <unordered_set>
template<     class Key,     class Hash = std::hash<Key>,     class KeyEqual = std::equal_to<Key>,     class Allocator = std::allocator<Key> > class unordered_multiset;		(since C++11)

Unordered multiset is an associative container that contains set of possibly non-unique objects of type Key. Search, insertion, and removal have average constant-time complexity.

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 value. This allows fast access to individual elements, since once hash is computed, it refers to the exact bucket the element is placed into.

std::unordered_multiset meets the requirements of Container, AllocatorAwareContainer, UnorderedAssociativeContainer.

Member types

Member type	Definition
key_type	Key
value_type	Key
size_type	Unsigned integral type (usually std::size_t)
difference_type	Signed integer type (usually std::ptrdiff_t)
hasher	Hash
key_equal	KeyEqual
allocator_type	Allocator
reference	value_type&
const_reference	const value_type&
pointer	std::allocator_traits<Allocator>::pointer
const_pointer	std::allocator_traits<Allocator>::const_pointer
iterator	ForwardIterator
const_iterator	Constant forward iterator
local_iterator	An iterator type whose category, value, difference, pointer and reference types are the same as iterator. This iterator can be used to iterate through a single bucket but not across buckets
const_local_iterator	An iterator type whose category, value, difference, pointer and reference types are the same as const_iterator. This iterator can be used to iterate through a single bucket but not across buckets

Member functions

(constructor)	constructs the unordered_multiset (public member function)
(destructor)	destructs the unordered_multiset (public member function)
operator=	assigns values to the container (public member function)
get_allocator	returns the associated allocator (public member function)
Iterators
begin cbegin	returns an iterator to the beginning (public member function)
end cend	returns an iterator to the end (public member function)
Capacity
empty	checks whether the container is empty (public member function)
size	returns the number of elements (public member function)
max_size	returns the maximum possible number of elements (public member function)
Modifiers
clear	clears the contents (public member function)
insert	inserts elements (public member function)
emplace	constructs element in-place (public member function)
emplace_hint	constructs elements in-place using a hint (public member function)
erase	erases elements (public member function)
swap	swaps the contents (public member function)
Lookup
count	returns the number of elements matching specific key (public member function)
find	finds element with specific key (public member function)
equal_range	returns range of elements matching a specific key (public member function)
Bucket interface
begin(int) cbegin(int)	returns an iterator to the beginning of the specified bucket (public member function)
end(int) cend(int)	returns an iterator to the end of the specified bucket (public member function)
bucket_count	returns the number of buckets (public member function)
max_bucket_count	returns the maximum number of buckets (public member function)
bucket_size	returns the number of elements in specific bucket (public member function)
bucket	returns the bucket for specific key (public member function)
Hash policy
load_factor	returns average number of elements per bucket (public member function)
max_load_factor	manages maximum average number of elements per bucket (public member function)
rehash	reserves at least the specified number of buckets. This regenerates the hash table. (public member function)
reserve	reserves space for at least the specified number of elements. This regenerates the hash table. (public member function)
Observers
hash_function	returns function used to hash the keys (public member function)
key_eq	returns the function used to compare keys for equality (public member function)

Non-member functions

operator==operator!=	compares the values in the unordered_multiset (function template)
std::swap(std::unordered_multiset) (C++11)	specializes the std::swap algorithm (function template)

Notes

The member types iterator and const_iterator may be aliases to the same type. Since iterator is convertible to const_iterator, const_iterator should be used in function parameter lists to avoid violations of the One Definition Rule.