class template
<ratio>

std::ratio_subtract

template <class R1, class R2> ratio_subtract;
Subtract ratios
This class template alias generates a ratio type that is the difference between the ratio types R1 and R2.

The resulting type is the same as if ratio_subtract was defined as:
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template <typename R1, typename R2>
using ratio_subtract = std::ratio < R1::num*R2::den-R2::num*R1::den, R1::den*R2::den >;

A program shall not cause any expression in the above definition to expand to values not representable as an intmax_t.

Template parameters

R1,R2
ratio types to be subtracted.

Member constants

The same as ratio (ratio_subtract is merely a template alias).
member constexprdescription
numNumerator
denDenominator

The values of num and den represent the result of the subtraction operation.

Member types

The same as ratio (ratio_subtract is merely a template alias).
member typedefinitiondescription
typeratio<num,den>The ratio type with the result of the subtraction.

Example

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// ratio_subtract example
#include <iostream>
#include <ratio>

int main ()
{
  typedef std::ratio<2,3> two_thirds;
  typedef std::ratio<1,2> one_half;

  typedef std::ratio_subtract<two_thirds,one_half> diff;

  std::cout << "diff = " << diff::num << "/" << diff::den;
  std::cout << " (which is: " << ( double(diff::num) / diff::den ) << ")" << std::endl;

  return 0;
}

Output:
diff = 1/6 (which is: 0.166667)


See also