Object-oriented Software in Ada 95

146 Case study: Design of a game
The procedure Announce communicates with the human player the result of the game.
procedure Announce(The:in Player; What:in State_Of_Game) is
begin
case What is
when Win =>
Put("Player "); Display( The.Plays_With );
Put(" has won");
when Lose =>
Put("Player "); Display( The.Plays_With );
Put(" has lost");
when Draw =>
Put("It's a draw");
when others =>
raise Constraint_Error;
end case;
New_Line;
end Announce;
end Class_Player;
9.7 Self-assessment
• What is the function of the class Player?
• What is the function of the class Cell?
• Could the recursive function no_turned in the class Board be written non-recursively?
• The procedure announce in the class Board has a case statement with a when others clause
that can never occur. Why is this clause necessary?
9.8 Exercises
• Better ‘reversi’
Modify the program to have a separate class for all input and output.
• Graphic ‘reversi’
The program could be modified by providing additional classes to present a graphical display of the
board. The display could enable the user to drop a counter into a cell selected by a using a mouse.
Describe the modifications required to implement this new version.
• Implementation of a graphic ‘Reversi’
Implement this new graphical version.
© M A Smith - May not be reproduced without permission