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std::ratio_multiply

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< cpp‎ | numeric‎ | ratio
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Defined in header <ratio>
template< class R1, class R2 >
using ratio_multiply = /* unspecified */;

The template alias std::ratio_multiply denotes the result of multiplying two exact rational fractions represented by the std::ratio instances R1 and R2. The result a std::ratio instance std::ratio<Num, Denom> where Num == R1::num * R2::num and Denom == R1::den * R2::den.

[edit] Member types

Member type Definition
type std::ratio<num, den>

[edit] Member constants

num
[static]
constexpr value of type std::intmax_t equal to sign(Num) * sign(Denom) * abs(Num) / gcd(Num, Denom)
(public static member constant)
den
[static]
constexpr value of type std::intmax_t equal to abs(Denom) / gcd(Num, Denom)
(public static member constant)

[edit] Example

#include <iostream>
#include <ratio>
 
int main()
{
    typedef std::ratio<2, 3> two_third;
    typedef std::ratio<1, 6> one_sixth;
    typedef std::ratio_multiply<two_third, one_sixth> r;
    std::cout << "2/3 * 1/6 = " << r::num << '/' << r::den << '\n';
}

Output:

2/3 * 1/6 = 1/9