std::equal_to

From cppreference.com
< cpp‎ | utility‎ | functional
 
 
 
Function objects


Function wrappers
(C++11)
(C++11)
(C++17)
Bind
(C++11)
Reference wrappers
(C++11)(C++11)
Operator wrappers
Negators
(deprecated)
(deprecated)

(deprecated)
(deprecated)
Searchers
Old binders and adaptors
(until C++17)
(until C++17)
(until C++17)
(until C++17)
(until C++17)(until C++17)(until C++17)(until C++17)
(until C++17)(until C++17)
(until C++17)(until C++17)

(until C++17)
(until C++17)(until C++17)(until C++17)(until C++17)
 
Defined in header <functional>
template< class T >
struct equal_to;
(until C++14)
template< class T = void >
struct equal_to;
(since C++14)

Function object for performing comparisons. Unless specialised, invokes operator== on type T.

Specializations

The standard library provides a specialization of std::equal_to when T is not specified, which leaves the parameter types and return type to be deduced.

function object implementing x == y deducing argument and return types
(class template specialization)
(since C++14)

Member types

type definition
result_type(deprecated in C++17) bool
first_argument_type(deprecated in C++17) T
second_argument_type(deprecated in C++17) T

Member functions

operator()
checks if the arguments are equal
(public member function)

std::equal_to::operator()

bool operator()( const T& lhs, const T& rhs ) const;
(until C++14)
constexpr bool operator()( const T& lhs, const T& rhs ) const;
(since C++14)

Checks whether lhs is equal to rhs.

Parameters

lhs, rhs - values to compare

Return value

true if lhs == rhs, false otherwise.

Exceptions

(none)

Possible implementation

constexpr bool operator()(const T &lhs, const T &rhs) const 
{
    return lhs == rhs;
}