std::equal_to - cppreference.com

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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 parameter and return types
(class template specialization) [edit]

(since C++14)

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)	`T`
`second_argument_type` (deprecated in C++17)(removed in C++20)	`T`

These member types are obtained via publicly inheriting std::binary_function<T, T, bool>.

(until C++11)

Member functions

checks if the arguments are equal
(public member function)

std::equal_to::operator()

bool operator()( const T& lhs, const T& rhs ) const;		(constexpr 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

May throw implementation-defined exceptions.

Possible implementation

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