std::ratio_divide(3)

NAME
std::ratio_divide - std::ratio_divide

Synopsis
   Defined in header <ratio>
   template< class R1, class R2 > (since C++11)
   using ratio_divide = /* see below */;
   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
// Run this code
 #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
   ratio_multiply multiplies two ratio objects at compile-time
   (C++11) (alias template)