std::ratio_equal - cppreference.com (original) (raw)

If the ratios R1 and R2 are equal, provides the member constant value equal true. Otherwise, value is false.

Contents

• 1 Helper variable template
• 2 Inherited from std::integral_constant
  • 2.1 Member constants
  • 2.2 Member functions
  • 2.3 Member types
  • 2.4 Possible implementation
  • 2.5 Example
  • 2.6 See also

[edit] Helper variable template

| template< class R1, class R2 > constexpr bool ratio_equal_v = ratio_equal<R1, R2>::value; | | (since C++17) | | ----------------------------------------------------------------------------------------------- | | ------------- |

Inherited from std::integral_constant

Member constants

| | true if R1::num == R2::num && R1::den == R2::den, false otherwise (public static member constant) | | ------------------------------------------------------------------------------------------------------ |

Member functions

| | converts the object to bool, returns value (public member function) | | ---------------------------------------------------------------------- | | | returns value (public member function) |

Member types

[edit] Possible implementation

template< class R1, class R2 > struct ratio_equal : public std::integral_constant < bool, R1::num == R2::num && R1::den == R2::den > {};

[edit] Example

#include #include   int main() { constexpr bool equ = std::ratio_equal_v<std::ratio<2,3>, std::ratio<6,9>>; static_assert(equ); std::cout << "2/3 " << (equ ? "==" : "!=") << " 6/9\n"; }

Output:

[edit] See also