std::negate<void>

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(until C++17*)
(until C++17*) (until C++17*) (until C++17*) (until C++17*)
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(until C++20*)
Defined in header <functional>
template <>
class negate< void > ;
(since C++14)

std::negate<> is a specialization of std::negate

Member types

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

Run this code
#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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