Introduction
A simplified version of the TicTacToe game has been written in Python. This was done as part of a lab in the "PCAP - Programming Essentials In Python" course on Cisco Networking Academy (https://www.netacad.com/portal/learning).
The program showcases the use of:
1. Tuples
2. Dictionaries
3. Two Dimensional Lists
4. while Loop
5. if statement
6. functions
Assumption: The computer always starts with an X in the middle of the board.
Also, the board of the game is numbered from 1 to 9 with position 5 containing the X that represents the first move of the computer. The initial state of the board will be as per Figure 1.
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| Figure 1: Initial state of the board. |
Algorithm
Taking into consideration the above assumption, the steps to be executed are as follows:
1. The board is displayed.
2. User enters a number between 1 to 9 where the 'O' is to be placed.
3. The updated board is displayed.
4. If user has won or there is a tie, stop the game.
5. The computer plays its move.
6. The updated board is displayed.
7. If the computer has won or there is a tie, stop the game.
Note: Steps 2 to 7 are executed in an infinite loop until there is a winner or there is a tie.
Implementation
The board of the game is represented as a two dimensional list called "board". It is a 3 by 3 array.
A dictionary, "dict_num_to_tup", is used to translate each position (1 to 9) in the board to its corresponding indices in the 2D array.
The following five functions have been defined:
1. display_board(board)
- It displays the current state of the board.
2. enter_move(board)
- It allows the user to enter a move. Some basic validations have been included in the function.
3. make_list_of_free_fields(board)
- It determines and build a list of free cells in the board. The list stores the indices of the free cells in the form of tuples.
4. victory_for(board, sign)
- It determines whether the "sign" passed as argument to the function has won the game or not.
5. draw_move(board)
- It allows the computer to play a move. A random number generator function has been used to simulate the move of the computer.
Code
Below is the python code. Same can also be executed by pressing the "play" button.
