Object-oriented Software in Ada 95

144 Case study: Design of a game
The procedure Status returns the current state of the game. This may be a draw if both players have passed
on their last go.
function Status ( The:in Board ) return State_Of_Game is
begin
if The.Score( The.Opponent ) = 0 then
return Win;
end if;
if (The.Sqrs'Length(1) * The.Sqrs'Length(2) =
The.Score(The.Opponent)+The.Score(The.Player)) or
(The.Last_Move(Black)=Pass and The.Last_Move(White)=Pass)
then
if The.Score(The.Opponent) = The.Score(The.Player)
then return Draw;
end if;
if The.Score(The.Opponent) < The.Score(The.Player)
then return Win;
else
return Lose;
end if;
end if;
return Play;
end;
Whilst not used, the function Contents is provided so that another user of the class Board could find the
contents of individual cells.
function Contents( The:in Board; X,Y:in Integer )
return Cell_Holds is
begin
return Holds( The.Sqrs( X, Y ) );
end Contents;
end Class_Board;
The package Class_Player is responsible for communicating with the actual human player playing the
game.
with Class_Counter, Class_Board;
use Class_Counter, Class_Board;
package Class_Player is
type Player is private;
procedure Set( The:in out Player; C:in Counter_Colour );
procedure Get_Move(The:in Player; Row,Column:out Integer);
function My_Counter( The:in Player ) return Counter;
procedure Announce( The:in Player; What:in State_Of_Game );
private
type Player is record
Plays_With : Counter;
end record;
end Class_Player;
--Player's counter
© M A Smith - May not be reproduced without permission