std::map<Key,T,Compare,Allocator>::value_compare (3) - Linux Manuals

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

NAME

std::map<Key,T,Compare,Allocator>::value_compare - std::map<Key,T,Compare,Allocator>::value_compare

Synopsis


class value_compare;


std::map::value_compare is a function object that compares objects of type std::map::value_type (key-value pairs) by comparing of the first components of the pairs.

Member types


Type Definition (until C++20)
result_type(deprecated in C++17) bool
first_argument_type(deprecated in C++17) value_type
second_argument_type(deprecated in C++17) value_type

Protected member objects


             the stored comparator
Compare comp (protected member object)

Member functions


              constructs a new value_compare object
constructor (protected member function)
              compares two values of type value_type
operator() (public member function)


 std::map<Key,T,Compare,Alloc>::value_compare::value_compare


protected:
value_compare( Compare c );


Initializes the internal instance of the comparator to c.

Parameters


c - comparator to assign


 std::map<Key,T,Compare,Alloc>::value_compare::operator()


bool operator()( const value_type& lhs, const value_type& rhs ) const;


Compares lhs.first and rhs.first by calling the stored comparator.

Parameters


lhs, rhs - values to compare

Return value


comp(lhs.first, rhs.first).

Exceptions


(none)

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