FT_ACCTWEEK()
 Return accounting week data
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 Syntax

      FT_ACCTWEEK( [ <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 52 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 accounting week
        aDateInfo[3] - The ending date of the accounting week

 Description

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

     An accounting period has the following characteristics:

     If the first week of the period contains 4 or more 'work'
     days, it is included in the period; otherwise, the first
     week was included in the prior period.

     If the last week of the period contains 4 or more 'work'
     days it is included in the period; otherwise, the last week
     is included in the next period.  This results in 13 week
     'quarters' and 4 or 5 week 'months'.  Every 5 or 6 years, a
     'quarter' will contain 14 weeks and the year will contain 53
     weeks.

 Examples

     // get info about accounting week containing 9/15/90
     aDateInfo := FT_ACCTWEEK( 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 accounting week 25 in year containing 9/15/90
     aDateInfo := FT_ACCTWEEK( CTOD("09/15/90"), 25 )
     ? aDateInfo[1]   //  199025
     ? aDateInfo[2]   //  06/17/89   beginning of week 25
     ? aDateInfo[3]   //  06/23/90   end of week 25

 Source: ACCTWEEK.PRG

 Author: Jo W. French dba Practical Computing