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

From cppreference.com
< cpp‎ | container‎ | flat map
 
 
 
 
size_type count( const Key& key ) const;
(1) (since C++23)
(constexpr since C++26)
template< class K >
size_type count( const K& x ) const;
(2) (since C++23)
(constexpr since C++26)

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 keys are always unique.
2) Returns the number of elements with key that compares equivalent to x.
This overload participates in overload resolution only if Compare is transparent. 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.

[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]