std::equal_to(3) | C++ Standard Libary | std::equal_to(3) |
NAME¶
std::equal_to - std::equal_to
Synopsis¶
Defined in header <functional>
template< class T > (until C++14)
struct equal_to;
template< class T = void > (since C++14)
struct equal_to;
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.
(since C++14)
equal_to<void> function object implementing x == y deducing argument
(C++14) and return types
(class template specialization)
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 (until C++11)
std::binary_function<T, T, bool>.
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¶
May throw implementation-defined exceptions.
Possible implementation¶
constexpr bool operator()(const T &lhs, const T &rhs)
const
{
return lhs == rhs;
}
See also¶
equal determines if two sets of elements are the same
(function template)
not_equal_to function object implementing x != y
(class template)
less function object implementing x < y
(class template)
ranges::equal_to function object implementing x == y
(C++20) (class)
2022.07.31 | http://cppreference.com |