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std:: ratio_not_equal

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ratio_not_equal
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定义于头文件 <ratio>
template < class R1, class R2 >
struct ratio_not_equal : std:: integral_constant < bool , /* 见下文 */ > { } ;
(C++11 起)

如果比例 R1 和 R2 不相等，则提供成员常量 value 等于 true 。否则， value 为 false 。

目录

辅助变量模板

template < class R1, class R2 >
constexpr bool ratio_not_equal_v = ratio_not_equal < R1, R2 > :: value ;
(C++17 起)

继承自 std:: integral_constant

成员常量

value
[static]
若 R1 :: num ! = R2 :: num || R1 :: den ! = R2 :: den 则为 true ，否则为 false
(公开静态成员常量)

成员函数

operator bool
转换对象为 bool 类型，返回 value
(公开成员函数)
operator()
(C++14)
返回 value
(公开成员函数)

成员类型

类型 定义
value_type bool
type std:: integral_constant < bool , value >

可能的实现 

template< class R1, class R2 >
struct ratio_not_equal : std::integral_constant <
                              bool,
                              !std::ratio_equal<R1, R2>
                         > {};

示例

运行此代码 
#include <ratio>
static_assert(std::ratio_not_equal_v<std::ratio<6, 9>, std::ratio<9, 6>>, "6/9 != 9/6");
int main() {}

参见

(C++11)
在编译时比较两个 ratio 对象是否相等
(类模板)