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.

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