-- Chapter 30 - Programming exercise 1
   generic
      type ITEM is range <>;   -- integer class only
   procedure Exchange_Data(X,Y : in out ITEM);

   procedure Exchange_Data(X,Y : in out ITEM) is
   Temp : ITEM;
   begin
      Temp := X;
      X := Y;
      Y := Temp;
   end Exchange_Data;

-- This is the beginning of the main program which uses the generic
-- procedure defined above.
with Exchange_Data;
with Ada.Text_IO;
use Ada.Text_IO;

procedure CH30_1 is

   package Int_IO is new Ada.Text_IO.Integer_IO(INTEGER);
   use Int_IO;

   type MY_INT is new INTEGER range 1..128;
   subtype SUB_INT is INTEGER range 1.. 55;

   procedure SwapInt is new Exchange_Data(INTEGER);
   procedure SwapNew is new Exchange_Data(MY_INT);
   procedure SwapSub is new Exchange_Data(SUB_INT);

   Index1 : INTEGER := 17;
   Index2 : INTEGER := 33;
   Limit1 : MY_INT  := 3;
   Limit2 : MY_INT  := 7;
   Small1 : SUB_INT := 13;
   Small2 : SUB_INT := 27;

begin

   SwapInt(Index1,Index2);
   SwapNew(Limit1,Limit2);
   SwapSub(Small1,Small2);
   SwapInt(Small1,Small2);

   Put(Index1);
   Put(Index2);
   New_Line;
   Put(INTEGER(Limit1));
   Put(INTEGER(Limit2));
   New_Line(2);

   SwapInt(Index1,INTEGER(Limit1));
   SwapNew(MY_INT(Index2),Limit2);

   Put(Index1);
   Put(Index2);
   New_Line;
   Put(INTEGER(Limit1));
   Put(INTEGER(Limit2));
   New_Line(2);

end CH30_1;




-- Note that it is legal to instantiate a copy of the generic
--   procedure for the subtype.  It is a waste of code however,
--   because the procedure for the parent type can be used for
--   the subtype as illustrated in line 44.

-- Result of Execution

--    33    17
--     7     3
--
--     7     3
--    33    17