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std:: ratio_equal

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Compile-time rational arithmetic
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ratio_equal
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헤더에 정의됨 <ratio>
template < class R1, class R2 >
struct ratio_equal : std:: integral_constant < bool , /* see below */ > { } ;
(C++11 이후)

비율 R1 과 R2 가 동일한 경우, 멤버 상수 value 를 true 로 설정합니다. 그렇지 않은 경우, value 는 false 입니다.

목차

헬퍼 변수 템플릿

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

std:: integral_constant 에서 상속됨

멤버 상수

value
[static]
true 만약 R1 :: num == R2 :: num && R1 :: den == R2 :: den 인 경우, false 그렇지 않은 경우
(public static member constant)

멤버 함수

operator bool
객체를 bool 로 변환, value 반환
(public member function)
operator()
(C++14)
value 반환
(public member function)

멤버 타입

타입 정의
value_type bool
type std:: integral_constant < bool , value >

가능한 구현 

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

예제

이 코드 실행 
#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";
}

출력: 

2/3 == 6/9

참고 항목

(C++11)
컴파일 타임에 두 ratio 객체의 불일치를 비교합니다
(클래스 템플릿)