std::equal_to
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Defined in header
<functional>
template< class T >
struct equal_to;
(until C++14)
struct equal_to;
template< class T = void >
struct equal_to;
(since C++14)
struct equal_to;
Function object for performing comparisons. Unless specialised, invokes operator== on type T.
Contents
[edit] 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.
(C++14)
(class template specialization) [edit]
[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)
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)[edit] Member functions
operator()
(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.
[edit] Exceptions
May throw implementation-defined exceptions.
Possible implementation
constexpr bool operator()(const T& lhs, const T& rhs) const { return lhs == rhs; }