std::ratio_subtract

 

C++

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ratio_equal (C++11)

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Defined in header <ratio>
template< class R1, class R2 > using ratio_subtract = /* unspecified */;

The template alias std::ratio_subtract denotes the result of subtracting 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::den - R2::num * R1::den and Denom == R1::den * R2::den.

Member types

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

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)

Example

Run this code

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

Output:

2/3 - 1/6 = 1/2