std::set<Key,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, which is either 1 or 0 since this container does not allow duplicates.
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 only participates in overload resolution if the qualified-id Compare::is_transparent is valid and denotes a type. 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 that compares equivalent to key or x, which is either 1 or 0 for (1).
Complexity
Logarithmic in the size of the container.
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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