...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Retrieves the day component (1-based).
constexpr std::uint8_t day() const;
A value of 1 represents the first day of the month. If this->valid() == true
,
this value is within the [1, last_month_day]
range (where last_month_day
is the last day of the month).
No-throw guarantee.