NAME¶

std::multiplies - std::multiplies

Synopsis¶

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

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

Member functions¶

operator() returns the product of two arguments
(public member function)

std::multiplies<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 product of lhs and rhs.

Parameters¶

lhs, rhs - values to multiply

Return value¶

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

Example¶

// Run this code

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

int main()
{
auto complex_multiplies = std::multiplies<void>{}; // “void” can be omitted
constexpr std::complex z1{1.0, 2.0}, z2{3.0, 4.0};

std::cout << std::showpos
<< complex_multiplies(z1, z2) << ' ' << z1 * z2 << '\n'
<< complex_multiplies(z1, 5.) << ' ' << z1 * 5. << '\n'
<< complex_multiplies(5., z1) << ' ' << 5. * z1 << '\n';
}

Output:¶

(-5,+10) (-5,+10)
(+5,+10) (+5,+10)
(+5,+10) (+5,+10)