std::chrono::operator==,<=>(std::chrono::day)

 

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通用实用程序 日期和时间 函数对象 格式化库 (C++20) bitset hash (C++11) 关系运算符 (C++20 中已弃用) rel_ops::operator!=rel_ops::operator>     rel_ops::operator<=rel_ops::operator>= 整数比较函数 cmp_equalcmp_lesscmp_less_than (C++20)(C++20)(C++20)    cmp_not_equalcmp_greatercmp_greater_than (C++20)(C++20)(C++20) in_range (C++20) 交换 和 类型操作 swap ranges::swap (C++20) exchange (C++14) declval (C++11) to_underlying (C++23) forward (C++11) forward_like (C++23) move (C++11) move_if_noexcept (C++11) as_const (C++17) 通用词汇类型 pair tuple (C++11) optional (C++17) any (C++17) variant (C++17) tuple_size (C++11) tuple_element (C++11) apply (C++17) make_from_tuple (C++17) expected (C++23) 基本字符串转换 to_chars (C++17) from_chars (C++17) chars_format (C++17) to_chars_result (C++17) from_chars_result (C++17)

 

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C 样式日期和时间

 

std::chrono::day

成员函数

day::day

day::operator++day::operator--

day::operator+=day::operator-=

day::operator unsigned

day::ok

非成员函数

operator==operator<=>

operator+operator-

operator<<

from_stream

operator""d

辅助类

formatter<std::chrono::day>

hash<std::chrono::day> (C++26)

 

定义在头文件 <chrono> 中
constexpr bool operator==( const std::chrono::day& x,                            const std::chrono::day& y ) noexcept;	(1)	(自 C++20 起)
constexpr std::strong_ordering operator<=>( const std::chrono::day& x,                                             const std::chrono::day& y ) noexcept;	(2)	(自 C++20 起)

比较两个 std::chrono::day x 和 y.

<、<=、>、>= 和 != 运算符分别从 operator<=> 和 operator== 合成。

返回值

1) unsigned(x) == unsigned(y)

2) unsigned(x) <=> unsigned(y)

示例

运行这段代码

#include <chrono>
#include <iostream>
 
int main()
{
    constexpr std::chrono::day x{13}, y{31};
    static_assert(x != y);
 
    if constexpr (constexpr auto res = x <=> y; res < 0)
        std::cout << "x is less than y\n";
    else if constexpr (res > 0)
        std::cout << "x is greater than y\n";
    else
        std::cout << "x and y are equal\n";
 
    using namespace std::literals::chrono_literals;
 
    static_assert
    (
        (6d < 9d) && (6d == 6d) && (6d <= 9d) &&
        (9d > 6d) && (9d != 6d) && (9d >= 6d)
    );
}

输出

x is less than y