cpp/chrono/year month weekday/year month weekday

Constructs a object.

@1@ Default constructor leaves the fields uninitialized. @2@ Constructs a object storing the year, the month , the weekday  and the weekday index. @3@ Constructs a object corresponding to the date represented by. For any object storing a valid date, converting it to  and back yields the same value. This constructor defines an implicit conversion from to. @4@ Constructs a object corresponding to the date represented by. Equivalent to.