std:: ratio_divide

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(C++11) ( until C++20* ) (C++17)
Compile-time rational arithmetic
Compile-time integer sequences
Defined in header <ratio>
template < class R1, class R2 >
using ratio_divide = /* see below */ ;
(since C++11)

The alias template std::ratio_divide denotes the result of dividing two exact rational fractions represented by the std::ratio specializations R1 and R2 .

The result is a std::ratio specialization std:: ratio < U, V > , such that given Num == R1 :: num * R2 :: den and Denom == R1 :: den * R2 :: num (computed without arithmetic overflow), U is std:: ratio < Num, Denom > :: num and V is std:: ratio < Num, Denom > :: den .

Notes

If U or V is not representable in std::intmax_t , the program is ill-formed. If Num or Denom is not representable in std::intmax_t , the program is ill-formed unless the implementation yields correct values for U and V .

The above definition requires that the result of std :: ratio_divide < R1, R2 > be already reduced to lowest terms; for example, std :: ratio_divide < std:: ratio < 1 , 12 > , std:: ratio < 1 , 6 >> is the same type as std:: ratio < 1 , 2 > .

Example

#include <iostream>
#include <ratio>
 
int main()
{
    using two_third = std::ratio<2, 3>;
    using one_sixth = std::ratio<1, 6>;
    using quotient = std::ratio_divide<two_third, one_sixth>;
    static_assert(std::ratio_equal_v<quotient, std::ratio<0B100, 0X001>>);
    std::cout << "(2/3) / (1/6) = " << quotient::num << '/' << quotient::den << '\n';
}

Output:

(2/3) / (1/6) = 4/1

See also

multiplies two ratio objects at compile-time
(alias template)