std::chrono::year::is_leap

来自cppreference.com
< cpp‎ | 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

*this 表示闰年则为 true ,否则为 false

示例

#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