std::flat_multimap<Key,T,Compare,KeyContainer,MappedContainer>::count

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Execution support library (C++26)

Technical specifications

Symbols index

External libraries

 

Containers library

Sequence

array (C++11)

vector

vector<bool>

inplace_vector (C++26)

deque

forward_list (C++11)

list

Associative

set

multiset

map

multimap

Unordered associative

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

Adaptors

stack

queue

priority_queue

flat_set (C++23)

flat_multiset (C++23)

flat_map (C++23)

flat_multimap (C++23)

Views

span (C++20)

mdspan (C++23)

Tables

Iterator invalidation

Member function table

Non-member function table

 

std::flat_multimap

Member types

Member functions

flat_multimap::flat_multimap    flat_multimap::operator= Modifiers flat_multimap::clear flat_multimap::erase flat_multimap::swap flat_multimap::extract flat_multimap::replace flat_multimap::insert flat_multimap::insert_range flat_multimap::emplace flat_multimap::emplace_hint Lookup flat_multimap::count flat_multimap::find flat_multimap::contains flat_multimap::equal_range flat_multimap::lower_bound flat_multimap::upper_bound Iterators flat_multimap::beginflat_multimap::cbegin flat_multimap::endflat_multimap::cend flat_multimap::rbeginflat_multimap::crbegin flat_multimap::rendflat_multimap::crend Capacity flat_multimap::size flat_multimap::max_size flat_multimap::empty Observers flat_multimap::key_comp flat_multimap::keys flat_multimap::value_comp flat_multimap::values

Non-member functions

swap(std::flat_multimap) erase_if(std::flat_multimap)     operator==operator<=>

Helper classes

uses_allocator<std::flat_multimap>

Tags

sorted_equivalent          sorted_equivalent_t

Deduction guides

 

size_type count( const Key& key ) const;	(1)	(since C++23)
template< class K > size_type count( const K& x ) const;	(2)	(since C++23)

Returns the number of elements with key that compares equivalent to the specified argument.

1) Returns the number of elements with key key.

2) Returns the number of elements with key that compares equivalent to the value x. This overload participates in overload resolution only if the qualified-id Compare::is_transparent is valid and denotes a type. It allows calling this function without constructing an instance of Key.

Parameters

key	-	key value of the elements to count
x	-	alternative value to compare to the keys

Return value

Number of elements with key that compares equivalent to key or x.

Complexity

Logarithmic in the size of the container plus linear in the number of elements found.

See also

find	finds element with specific key (public member function)
equal_range	returns range of elements matching a specific key (public member function)