{@@@@@@@@@@@ copyright (C) 1984 by Neil J. Rubenking @@@@@@@@@@@@@@@@@@@@@@@@
The purchaser of these procedures and functions may include them in COMPILED
programs freely, but may not sell or give away the source text.

   This program is a simple demo of the use of POINTERS to produce
   a QUEUE.  Please note that the amount of memory set aside for
   the QUEUE is ZERO.  As each item is added, a chunk of memory is
   devoted to it.  This is very often much more efficient than
   an ARRAY, which must be declared to be a specific size.


}


{@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@}
type
  ItemType = array[1..1016] of byte;
{$I queue.lib}
{$I kavail.lib}
{$I getkeys.lib}

var
  Klist, Kpointer : ListType;
  DummyItem       : ItemType;
  N, Initial_K    : integer;
  C, D            : char;
{@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@}
begin
  window(10,1,70,25);
  ClrScr;
  WriteLn('This program shows the effect of adding items to a queue.');
  WriteLn('After each addition, it shows the memory available in K');
  WriteLn('Since each item is one K in size (1016 bytes of data and');
  WriteLn('8 bytes for the pointer), additions are clearly visible.');
  WriteLn('    Each time you press a key, an item will be added.  To');
  WriteLn('stop adding and dispose of all the items, press <Esc>');
  WriteLn;
  Initial_K := K_Available;
  WriteLn('You start with ',K_available,'K available.');
  window(10,10,70,25);
  for N := 1 to 1016 do
    DummyItem[N] := N and $00FF;    { I have heard that for reducing an }
                                    { integer to a byte, "and $00FF" is }
                                    { much faster than "mod 256".       }
  N := 0;
  repeat
    GetKeys(C,D);
    N := N + 1;
    AddItem(DummyItem,KList,KPointer);
    WriteLn('Added ',N,' items.  ',K_available,'K available.');
  until (C = #27) and (D = #0);
  WriteLn;
  WriteLn('You started with ',Initial_K,'K bytes.');
  WriteLn('After adding ',N,' items, you have ',K_available,'K bytes.');
  WriteLn;
  DisposeAll(KList);
  WriteLn('I just DISPOSEd of the list.  You have ',K_available,'K bytes.');
end.

S SCREEN WAS NOT READ FROM THAT FILE.');
MakeScreen(Pops[4][6],15,
'