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std::less_equal

From cppreference.com
< cpp‎ | utility‎ | functional
 
 
 
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Defined in header <functional>
template< class T >
struct less_equal;
(until C++14)
template< class T = void >
struct less_equal;
(since C++14)

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

Contents

[edit] Specializations

A specialization of std::less_equal for any pointer type yields a total order, even if the built-in operator<= does not.

If the function call operator of the specialization std::less_equal<void> calls a built-in operator comparing pointers, it yields a total order, even if the built-in operator<= does not. (since C++14)

The standard library provides a specialization of std::less_equal 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) [edit]
(since C++14)

[edit] 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

[edit] Member functions

operator()
checks if the first argument is less than or equal to the second
(public member function)

std::less_equal::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 if lhs is less than or 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;
}