NAME¶

std::chrono::year::is_leap - std::chrono::year::is_leap

Synopsis¶

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

Determines if *this represents a leap year in the proleptic Gregorian calendar.

*this represents a leap year if the stored year value

* is divisible by 4 and not divisible by 100; or
* is divisible by 400.

Return value¶

true if *this represents a leap year, otherwise false.

Example¶

// Run this code

#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";
}
}
}

Output:¶

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