virtual iter_type do_put(iter_type next, ios_base& x,
tm *pt, char fmt, char mod = 0) const;The virtual protected member function generates sequential elements beginning at next from time values stored in the
object *pt, of type tm. The function returns an iterator designating the next place
to insert an element beyond the generated output.
The output is generated by the same rules used by strftime, with a last argument of pt, for
generating a series of char elements into an array. (Each such char element is assumed to map to an equivalent element
of type E by a simple one-to-one mapping.) If mod equals zero, the effective format is "%F", where F equals fmt.
Otherwise, the effective format is "%MF", where M equals mod.