std::modulus<void> - cppreference.com

From cppreference.com


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

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

Nested types

Member functions

returns the modulus of two arguments
(public member function)

std::modulus<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 remainder of the division of lhs by rhs.

Parameters

lhs, rhs

values to divide

Return value

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

Example

#include <functional>
#include <iostream>

struct M
{
    M(int x) { std::cout << "M(" << x << ");\n"; }
    M() {}
};

auto operator%(M, M) { std::cout << "operator%(M, M);\n"; return M{}; }
auto operator%(M, int) { std::cout << "operator%(M, int);\n"; return M{}; }
auto operator%(int, M) { std::cout << "operator%(int, M);\n"; return M{}; }

int main()
{
    M m;
    
    // 42 is converted into a temporary object M{42}
    std::modulus<M>{}(m, 42);    // calls operator%(M, M)
    
    // no temporary object
    std::modulus<void>{}(m, 42); // calls operator%(M, int)
    std::modulus<void>{}(42, m); // calls operator%(int, M)
}

Output:

M(42);
operator%(M, M);
operator%(M, int);
operator%(int, M);