# std::chrono::year::is_leap

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< cpp‎ | chrono‎ | year

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

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