-- Chapter 20 - Programming exercise 1
with Ada.Text_IO, Ada.Integer_Text_IO;
use Ada.Text_IO, Ada.Integer_Text_IO;

procedure CH20_1 is

   type POWER is (GAS, STEAM, DIESEL, NONE);

   package Enum_IO is new Ada.Text_IO.Enumeration_IO(POWER);
   use Enum_IO;

   type VEHICLE (Engine : POWER) is
      record
         Model_Year : INTEGER range 1888..1992;
         Wheels     : INTEGER range 2..18;
         case Engine is
            when GAS    => Cylinders   : INTEGER range 1..16;
            when STEAM  => Boiler_Size : INTEGER range 5..22;
                           Coal_Burner : BOOLEAN;
            when DIESEL => Fuel_Inject : BOOLEAN;
            when NONE   => Speeds      : INTEGER range 1..15;
         end case;
      end record;

   Ford    : VEHICLE(GAS);
   Truck   : VEHICLE(DIESEL);
   Schwinn : VEHICLE(NONE);
   Stanley : VEHICLE(STEAM);

begin

   Ford.Model_Year := 1956;       -- Component assignment
   Ford.Wheels := 4;
   Ford.Cylinders := 8;

   Ford := (GAS, 1956, 4, 8);     -- Positional aggregate assignment

                                  -- Named aggregate assignment
   Ford := (Model_Year => 1956, Cylinders => 8, Engine => GAS,
                                                      Wheels => 4);

   Stanley.Model_Year := 1908;
   Stanley.Wheels := 4;
   Stanley.Boiler_Size := 21;
   Stanley.Coal_Burner := FALSE;
                                  -- Mixed aggregate assignment
   Stanley := (STEAM, 1908, 4, Coal_Burner => FALSE,
                                                Boiler_Size => 21);

   Schwinn.Speeds := 10;
   Schwinn.Wheels := 2;
   Schwinn.Model_Year := 1985;

   Truck.Model_Year := 1966;
   Truck.Wheels := 18;
   Truck.Fuel_Inject := TRUE;

   Put("Stanley engine type is ");
   Put(Stanley.Engine);
   Put(", and has");
   Put(Stanley.Wheels,3);
   Put_Line(" wheels.");

   Put("The truck is a");
   Put(Truck.Model_Year,5);
   Put(" and has");
   Put(Truck.Wheels,3);
   Put_Line(" wheels.");

end CH20_1;




-- Result of Execution

-- Stanley engine type is STEAM, and has  4 wheels.
-- The truck is a 1966 and has 18 wheels.