std::minus<void> - cppreference.com

From cppreference.com


`template<> class minus<void>;`		(since C++14)

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

Member types

Member functions

returns the difference of two arguments
(public member function)

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

`template< class T, class U > constexpr auto operator()( T&& lhs, U&& rhs ) const -> decltype(std::forward<T>(lhs) - std::forward<U>(rhs));`

Returns the difference of lhs and rhs.

Parameters

lhs, rhs

values to subtract

Return value

std::forward<T>(lhs) - std::forward<U>(rhs).

Example

#include <complex>
#include <functional>
#include <iostream>

int main()
{
    auto complex_minus = std::minus<void>{}; // “void” can be omitted
    constexpr std::complex<int> z(4, 2);
    std::cout << complex_minus(z, 1) << '\n';
    std::cout << (z - 1) << '\n';
}

Output: