Namespaces
Variants
Views
Actions

std::multimap<Key,T,Compare,Allocator>::count

From cppreference.com
< cpp‎ | container‎ | multimap
 
 
 
 
size_type count( const Key& key ) const;
(1)
template< class K >
size_type count( const K& x ) const;
(2) (since C++14)

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.

Contents

[edit] Parameters

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

[edit] Return value

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

[edit] Complexity

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

Notes

Feature-test macro Value Std Feature
__cpp_lib_generic_associative_lookup 201304L (C++14) Heterogeneous comparison lookup in associative containers; overload (2)

[edit] Example

[edit] See also

finds element with specific key
(public member function) [edit]
returns range of elements matching a specific key
(public member function) [edit]