std::map<Key,T,Compare,Allocator>::value_compare
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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.
Contents
[edit] Member types
Type
Definition
result_type (deprecated in C++17)(removed in C++20)
bool
first_argument_type (deprecated in C++17)(removed in C++20)
value_type
second_argument_type (deprecated in C++17)(removed in C++20)
value_type
These member types are obtained via publicly inheriting std::binary_function <value_type, value_type, bool>.
(until C++11)[edit] Protected member objects
Compare comp
(protected member object)
[edit] Member functions
std::map<Key,T,Compare,Alloc>::value_compare::value_compare
protected:
value_compare( Compare c );
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)
[edit] Exceptions
May throw implementation-defined exceptions.