CS302 Lectures 1 & 2 Home Page

CS302 Lectures 1 & 2: Tic Tac Toe, version 1

In This Page: Files | Class Diagrams | Execution Diagrams

This example illustrates the basics of object-oriented programming with the common game, Tic Tac Toe. This version does not use statements that haven't been learned yet (i.e. control structures such as if or while statements).

Files

Source Code (main Class): TicTacToe1.java
Java Documents: Rules, Player, Board, Move, and Mark Classes
Executable Program (Windows):TicTacToe1.exe, TicTacToe1.zip

1. download both files into the same directory

2. run TicTacToe.exe

Class Diagrams

Execution Diagrams

code: board = new Board();

execution: The main method of the TicTacToe1 class sends a message to the Board class requesting a new Board object to be constructed. (not shown: the address of the new object is returned by the new operator)

result: board refers to the newly constructed Board object having an empty grid.

code: playerX = new Player("X");

execution: The main method of the TicTacToe1 class sends a message with the argument X to the Player class requesting a new Player object to be constructed. (not shown: the address of the new object is returned by the new operator)

result: playerX refers to the newly constructed Player object. Assume a program user enters the name Jim.

code step 1: board.display();

execution: The main method of the TicTacToe1 class sends a display message to board.

result: A character representation of the board is displayed in the console window.

col 1:2:3

row 1: | |
-----
row 2: | |
-----
row 3: | |

code step 2: move = playerX.getMove();

execution: The main method of the TicTacToe1 class sends a getMove message to playerX, which then returns a Move object (see result for the complete Move object diagram).

result: move refers to the returned Move object. Assume a program user enters row and column coordinates, which playerX uses to construct the returned Move object.

code step 3: Rules.checkMove(move, board);

execution: The main method of the TicTacToe1 class sends to the Rules class a checkMove message with references to the move and board objects.

result: An error message is displayed and the program terminates if the move is invalid, otherwise the program continues execution.

Invalid Move, cell Taken.

code step 4: player.getMark();

execution: The main method of the TicTacToe1 class sends a getMark message to playerX, which then returns a Mark object (see result for the complete Mark object diagram).

result: mark refers to the returned Mark object.

code step 5: board.markMove(move, board, mark);

execution: The main method of the TicTacToe1 class sends a markMove message to board.

result: The grid has the mark recorded as shown in next code step.

repeat code step 1: board.display();

col 1:2:3

row 1: | |
-----
row 2: |X|
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row 3: | |