Comment
==========================================================

QuickSort program written in MarxMenu. Works like DOS sort
program. This shows parameter passing and recursive
programming.

Usage: DIR|MARXMENU SORT|MORE
       MARXMENU SORT INFILE OUTFILE

==========================================================
EndComment

ClearScreenOnExit Off

var SortBuf Middle


ReadTextFile  (ParamStr(2),SortBuf)

Sort(1,NumberOfElements(SortBuf))

WriteTextFile (ParamStr(3),SortBuf)


Procedure Sort (L,R)
var I,J
   I = L
   J = R
   Middle = SortBuf[(L+R)/2]
   repeat
      while SortBuf[I] < Middle
         I = I + 1
      endwhile
      while Middle < SortBuf[J]
         J = J - 1
      endwhile
      if I <= J
         Middle = SortBuf[J]
         SortBuf[J] = SortBuf[I]
         SortBuf[I] = Middle
         I = I + 1
         J = J - 1
      endif
   until I > J
   if (J - L) < (R - I)
      if L < J then Sort(L,J);
      if I < R then Sort(I,R);
   else
      if I < R then Sort(I,R);
      if L < J then Sort(L,J);
   endif
EndProc