std::chrono::year::is_leap

constexpr bool is_leap() const noexcept;

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.