Exploring C++20 std::chrono - Calendar Types

Before C++20, <chrono> gave us a solid foundation for working with clocks, durations, and time points - but it didn’t really know anything about the civil calendar. If you needed to represent “March 15”, check whether a date is valid, compute “the third Monday of November”, or add a few months to a date, you had to rely on custom utilities, std::tm , or external libraries like Howard Hinnant’s…