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

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. This is either 1 or 0 since this container does not allow duplicates.
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, which, for overload (1), is either 1 or 0.

Complexity

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

Example

See also

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

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