size_type count( const Key& key ) const;
(1) (since C++11)

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


[edit] Parameters

key - key value of the elements to count

[edit] Return value

Number of elements with key key.

[edit] Complexity

linear in the number of elements with key key on average, worst case linear in the size of the container.

[edit] See also

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