FT_WEEK()
 Return calendar or fiscal week data
------------------------------------------------------------------------------

 Syntax

      FT_WEEK( [ <dGivenDate> ], [ <nWeekNum> ] ) -> aDateinfo

 Arguments

     <dGivenDate> is any valid date in any date format.  Defaults
     to current system date if not supplied.

     <nWeekNum> is a number from 1 to 53 signifying a week.
     Defaults to current week if not supplied.

 Returns

     A three element array containing the following data:

        aDateInfo[1] - The year and week as a character string "YYYYWW"
        aDateInfo[2] - The beginning date of the week
        aDateInfo[3] - The ending date of the week

 Description

     FT_WEEK() returns an array containing data about the week
     containing the given date.

     Normally the return data will be based on a year beginning
     on January 1st with weeks beginning on Sunday.

     The beginning of year date and/or beginning of week day can be
     changed by using FT_DATECNFG(), which will affect all subsequent
     calls to FT_WEEK() until another call to FT_DATECNFG().

     The beginning of year date and beginning of week day may be reset
     to January 1 and Sunday by calling FT_DATECNFG() with no
     parameters.

 Examples

     // get info about week containing 9/15/90
     aDateInfo := FT_WEEK( CTOD("09/15/90") )
     ? aDateInfo[1]   //  199037       (37th week)
     ? aDateInfo[2]   //  09/09/90     beginning of week 37
     ? aDateInfo[3]   //  09/15/90     end of week 37

     // get info about week 25 in year containing 9/15/90
     aDateInfo := FT_WEEK( CTOD("09/15/90"), 25 )
     ? aDateInfo[1]   //  199025
     ? aDateInfo[2]   //  06/17/90   beginning of week 25
     ? aDateInfo[3]   //  06/23/90   end of week 25

     // get info about week 25 in current year( 1991 )
     aDateInfo := FT_WEEK( , 25 )
     ? aDateInfo[1]   //  199025
     ? aDateInfo[2]   //  06/16/91   beginning of week 25
     ? aDateInfo[3]   //  06/22/91   end of week 25

 Source: WEEK.PRG

 Author: Jo W. French dba Practical Computing