Contributor: KIM KOKKONEN {A function and test program for computing the work week under one common definition. Written 94/10/05, Kim Kokkonen, TurboPower Software } uses opdate; {tpdate ok too} function WeekOfYear(Julian : Date) : Integer; {-Return the week-of-year from a julian date. As defined here, the week always starts on a Sunday. Week 1 starts on the first Sunday of the year. Returns 0 for days earlier than that, and -1 for invalid dates.} var Day, Month, Year : Integer; FirstJulian : Date; FirstDay : DayType; begin {Exit for invalid dates} if (Julian < MinDate) or (Julian > MaxDate) then begin WeekOfYear := -1; exit; end; {Compute FirstJulian, the julian date for the first Sunday in the year} DateToDMY(Julian, Day, Month, Year); FirstJulian := DMYToDate(1, 1, Year); FirstDay := DayOfWeek(FirstJulian); if FirstDay <> Sunday then inc(FirstJulian, 7-Ord(FirstDay)); if Julian < FirstJulian then WeekOfYear := 0 else WeekOfYear := (Julian-FirstJulian+7) div 7; end; var s : string; d : date; begin repeat Write('Enter date (dd/mm/yy): '); ReadLn(s); if s = '' then halt; if (Length(s) = 8) and (s[3] = '/') and (s[6] = '/') then begin d := DateStringToDate('dd/mm/yy', s); WriteLn('Week: ', WeekOfYear(d)); end else WriteLn('Invalid date format'); until False; end.