reservation_system.ads

Ada 2005 Training Notes.

package Reservation_System is
   type Position is (Aisle, Window);
   type Meal_Type is(Green, White, Red);

   type Reservation is tagged
      record
         Flight_Number: Integer;
         Data_Of_Travel: Integer;
         Seat_Number: String(1..3) := "   ";
      end record;

   procedure Make(R: in out Reservation);
   procedure Select_Seat(R: in out Reservation);


   type Basic_Reservation is new Reservation with null record;
   --

   type Nice_Reservation is new Reservation with
      record
         Seat_Sort: Position;
         Food: Meal_Type;
      end record;

   overriding
   procedure Make(NR: in out Nice_Reservation);	-- Overrides
   procedure Order_Meal(NR: in out Nice_Reservation);

   type Posh_Reservation is new Nice_Reservation with
      record
         Destination: Integer;
      end record;

   --
   -- override keyword is optional
   -- indicates to the compiler that this method is overriden by
   -- the derived type
   --
   overriding
   procedure Make(PR: in out Posh_Reservation); -- Overrides
   procedure Arrange_Limo(PR: in Posh_Reservation);

   procedure Process_Reservation_Request(Request: in out Reservation'Class);


   --
   -- Use Reservation_Ptr to define heterogen containers of Reservation types.
   -- Reservation_Ptr can access all types of Reservation derived objects.
   --
   type Reservation_Ptr is access Reservation'Class;

   type Cell is
      record
         Next: access Cell;	-- Anonymous type
         Element: Reservation_Ptr;
      end record;

   List: access Cell;

   procedure Process_Reservation(RP: in Reservation_Ptr);

   procedure Process_Reservations(Reservations: access Cell);


   --
   -- Abstract types
   --
   type T is abstract tagged
      record
         I: Integer;
      end record;

   procedure Op(X:T) is abstract;




end Reservation_System;