std:: ratio_equal

From cppreference.com
C++
Metaprogramming library
Type traits
Type categories
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
Type properties
(C++11)
(C++11)
(C++11)
(C++11)
(C++14)
(C++11)
(C++17)
(C++23)
(C++11) (deprecated in C++26)
(C++11)
(C++11)
(C++11) ( until C++20* )
(C++11) (deprecated in C++20)
(C++11)
(C++11)
(C++20)
(C++20)
(C++23)
(C++17)
Type trait constants
(C++11) (C++17) (C++11) (C++11)
Metafunctions
(C++17)
(C++17)
(C++17)
Supported operations
Relationships and property queries
Type modifications
Type transformations
(C++11) (deprecated in C++23)
(C++11) (deprecated in C++23)
(C++11)
(C++20)
(C++11)
(C++17)

(C++11)
(C++11)
(C++20)
(C++11)
(C++11) ( until C++20* ) (C++17)
(C++20)
Compile-time rational arithmetic
Compile-time integer sequences
(C++14)
Compile time rational arithmetic
(C++11)
Arithmetic
(C++11)
(C++11)
(C++11)
(C++11)
Comparison
ratio_equal
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
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 >
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

Run this code 
#include <iostream>
#include <ratio>
 
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: 

2/3 == 6/9

See also

(C++11)
compares two ratio objects for inequality at compile-time
(class template)
Retrieved from " https://en.cppreference.com/mwiki/index.php?title=cpp/numeric/ratio/ratio_equal&oldid=176482 "