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Difference between revisions of "cpp/numeric/ratio/ratio equal"

From cppreference.com
< cpp‎ | numeric‎ | ratio
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template< class R1, class R2 >
 
template< class R1, class R2 >
 
struct ratio_equal : std::integral_constant;
 
struct ratio_equal : std::integral_constant;
 
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If the ratios R1 and R2 are equal, provides the member constant {{tt|value}} equal {{c|true}}. Otherwise, {{tt|value}} is {{c|false}}.
 
If the ratios R1 and R2 are equal, provides the member constant {{tt|value}} equal {{c|true}}. Otherwise, {{tt|value}} is {{c|false}}.

Revision as of 20:24, 31 May 2013

 
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ratio_equal
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Defined in header <ratio>
template< class R1, class R2 >
struct ratio_equal : std::integral_constant;

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

[edit]

Contents

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()
{
    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
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