std::ratio_equal

< cpp‎ | numeric‎ | ratio
Defined in header <ratio>
template< class R1, class R2 >
struct ratio_equal : std::integral_constant<bool, /* see below */> { };
 (since C++11)

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

Helper variable template

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

Inherited from std::integral_constant

Member constants

value
[static]
 true if R1::num == R2::num && R1::den == R2::den , false otherwise
(public static member constant)

Member functions

operator bool
 converts the object to bool, returns value
(public member function)
operator()
(C++14)
 returns value
(public member function)

Member types

Type Definition
value_type bool
type std::integral_constant<bool, value>

Possible implementation

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

Example

#include <iostream>
#include <ratio>
 
int main()
{
    if(std::ratio_equal<std::ratio<2,3>, std::ratio<4,6>>::value) {
        std::cout << "2/3 == 4/6\n";
    } else {
        std::cout << "2/3 != 4/6\n";
    }
}

Output:

2/3 == 4/6

See also