std::set::count

 

C++

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size_type count( const Key& key ) const;	(1)
template< class K > size_type count( const K& x ) const;	(2)	(since C++14)

1) Returns the number of elements with key key, which 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. These templates only participate in overload resolution if the type Compare::is_transparent exists. They allow 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 key, that is either 1 or 0

Complexity

Logarithmic in the size of the container.

See also

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