function WeeksBetween(const ANow: TDateTime; const AThen: TDateTime): Integer;
int __fastcall WeeksBetween(System::TDateTime ANow, System::TDateTime AThen);
Returns the number of whole weeks between two specified TDateTime values.
Call WeeksBetween to obtain the difference, in weeks, between two TDateTime values. WeeksBetween counts only whole Weeks. Thus, WeeksBetween reports the difference between January 1 at 12:00 A.M. and Jan 6 at 11:58 P.M. as 0, because the difference is one minute short of an entire week.