-- Chapter 30 - Programming exercise 3
   generic
      type ITEM is private;
   procedure Exchange_Data(X, Y : in out ITEM);

   procedure Exchange_Data(X, Y : in out ITEM) is
   Temp : ITEM;
   begin
      Temp := X + 1;   -- This should produce an error
      X := Y;
      Y := Temp;
   end Exchange_Data;



   generic
      type ANOTHER_ITEM is range <>;   -- Integer class only
   function Average(X, Y : ANOTHER_ITEM) return ANOTHER_ITEM;

   function Average(X, Y : ANOTHER_ITEM) return ANOTHER_ITEM is
      Temporary : ANOTHER_ITEM;
   begin
      Temporary := (X + Y) / 2;
      return Temporary;
   end Average;





-- This is the beginning of the main program which uses the generic
-- procedure and function defined above.

with Exchange_Data, Average;
with Ada.Text_IO, Ada.Integer_Text_IO, Ada.Float_Text_IO;
use Ada.Text_IO, Ada.Integer_Text_IO, Ada.Float_Text_IO;

procedure CH30_3 is

   type NEW_TYPE is new INTEGER range 122..12345;

   type MY_RECORD is
      record
         My_Grade : INTEGER range 1..128;
         My_Class : CHARACTER;
      end record;

   procedure Swap is new Exchange_Data(INTEGER);
   procedure Swap is new Exchange_Data(MY_RECORD);
   procedure Swap is new Exchange_Data(FLOAT);
   procedure Swap is new Exchange_Data(NEW_TYPE);
   procedure Swap is new Exchange_Data(CHARACTER);
   procedure Trade is new Exchange_Data(CHARACTER);
   procedure Exchange is new Exchange_Data(CHARACTER);
   procedure Puppy is new Exchange_Data(CHARACTER);

   function Mean is new Average(INTEGER);
   function Mean is new Average(NEW_TYPE);
   function Swap is new Average(INTEGER);    -- This is dumb to do,
                                             --  but it is legal.

   Index1 : INTEGER := 117;
   Index2 : INTEGER := 123;
   Data1  : MY_RECORD := (15,'A');
   Data2  : MY_RECORD := (91,'B');
   Real1  : FLOAT := 3.14;
   Real2  : FLOAT := 77.02;
   Value1 : NEW_TYPE := 222;
   Value2 : NEW_TYPE := 345;

begin

   Put(Real1, 4, 2, 0);
   Put(Real2, 4, 2, 0);
   New_Line;
   Swap(Real1, Real2);
   Put(Real1, 4, 2, 0);
   Put(Real2, 4, 2, 0);
   New_Line(2);

   Put(Index1);
   Put(Index2);
   New_Line;

   Swap(Index1, Index2);
   Swap(Data1, Data2);

   Put(Index1);
   Put(Index2);
   New_Line;

                  -- Now to exercise some of the functions

   Index1 := Mean(Index2, 16);
   Value1 := Mean(Value2, Value2 + 132);
   Index1 := Swap(Index1, Index2 + 12);  -- This actually gets the
                                         --  mean of the inputs.

end CH30_3;




-- Result of Execution

-- Compile error,
-- Line 9 - Illegal operation for a private type, type clash.