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std::negate<void>

Defined in header <functional> 
template<>
class negate<void>;
 (since C++14)

std::negate<> is a specialization of std::negate with parameter and return type deduced.

Nested types

Nested type Definition
is_transparent unspecified

Member functions

operator()
returns its negated argument
(public member function)

std::negate<void>::operator()

template< class T >
constexpr auto operator()( T&& arg ) const
    -> decltype(-std::forward<T>(arg));

Returns the result of negating arg.

Parameters

arg - value to negate

Return value

-std::forward<T>(arg).

Example

#include <complex>
#include <functional>
#include <iostream>
 
int main()
{
    auto complex_negate = std::negate<void>{}; // “void” can be omitted
    constexpr std::complex z(4, 2);
    std::cout << z << '\n';
    std::cout << -z << '\n';
    std::cout << complex_negate(z) << '\n';
}

Output:

(4,2)
(-4,-2)
(-4,-2)

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