$IF 0

 Alphabetizing a list in PowerBASIC is as easy as invoking the ARRAY SORT
 statement on any array which contains a list of things to sort, and because
 PowerBASIC allows you to create arrays up to 640K in size, this is quite
 a powerful feature, but what if you have to sort a list larger that that
 (like 100 Megabytes)?  You need to sort the data on disk within a random
 access file.  You can use the BUBBLE sort, which is referred to as the
 "demon of exchange" since it can literally take DAYS to complete, or you
 can incorporate the "Quick Sort" developed by C.A.R. Hoare, which is the
 fastest sorting algorithm known to man.  Here it is, in PowerBASIC:

$ENDIF

SUB QUIKSORT(Fi$, Reclen) PUBLIC 'Fi$ is the file, Reclen is the record length
  OPEN Fi$ FOR BINARY AS #1
    QuickSort LOF(1)\Reclen, Reclen
  CLOSE #1
END SUB


 SUB QuickSort(Count, Reclen)
  QuickSort2 0, Count-1, Reclen
 END SUB

SUB QuickSort2(Port, Starboard, Reclen)
  locate 6,1: PRINT INT(Port/LOF(1)* 1000);"%"

  i=Port:j=Starboard

  X$=Item$((Port+Starboard)\2, Reclen)

  DO
    DO WHILE Item$(i,Reclen)<X$ AND i<Starboard:INCR i:LOOP
    DO WHILE Item$(j,Reclen)>X$ AND j>Port :DECR j:LOOP

    IF i<=j THEN
      CALL SWAPITEMS(i,j,Reclen)
      INCR i: DECR j:
    END IF
  LOOP WHILE i<=J

  IF Port < j THEN CALL QuickSort2(Port, J, Reclen)
  IF i < Starboard THEN CALL QuickSort2(i, Starboard, Reclen)
END SUB

FUNCTION Item$(number, Reclen)
  SEEK #1, Number*Reclen
  Get$ 1, Reclen, I$
  Item$=I$
END FUNCTION

SUB SWAPITEMS(a,b, Reclen)
  Seek #1, a*Reclen
  Get$ 1, Reclen, A$
  Seek #1, b*Reclen
  Get$ 1, Reclen, B$
  Seek #1, a*Reclen
  PUT$ #1, B$
  Seek #1, b*Reclen
  PUT$ #1, A$
END SUB