std::chrono::year::is_leap

 

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std::chrono::year

成员函数

year::year

year::operator++year::operator--

year::operator+=year::operator-=

year::operator+year::operator-

year::is_leap

year::operator int

year::ok

year::min

year::max

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formatter<std::chrono::year>

 

constexpr bool is_leap() const noexcept;		(C++20 起)

确定 *this 是否表示外推格里高利历中的闰年。

若存储的年份值满足下列条件则 *this 表示闰年

• 被 4 整除且不被 100 整除；或
• 被 400 整除。

返回值

若 *this 表示闰年则为 true ，否则为 false 。

示例

运行此代码

#include <iostream>
#include <chrono>
 
int main()
{
    using namespace std::chrono_literals;
    for (const std::chrono::year y : {2020y, 2021y, 2000y, 3000y}) {
        if (const int iy{ static_cast<int>(y) }; y.is_leap()) {
            std::cout << iy << " is a leap year because it is divisible by "
                      << (iy % 400 == 0 ? "400\n" : "4 and not divisible by 100\n");
        } else {
            std::cout << iy << " is not a leap year\n";
        }
    }
}

输出：

2020 is a leap year because it is divisible by 4 and not divisible by 100
2021 is not a leap year
2000 is a leap year because it is divisible by 400
3000 is not a leap year