tic-tac-toe.py

class TicTacToe:
    def __init__(self):
        # Initialise an empty board
        self.board = ['-' for _ in range(9)]
        self.current_player = 'X'  # X will start
    
    def make_move(self, position):
        """Make a move on the board."""
        if self.board[position] == '-':
            self.board[position] = self.current_player
            self.switch_player()
            return True
        else: return False  # illegal move
    
    def switch_player(self):
        """Switch the current player."""
        self.current_player = 'O' if self.current_player == 'X' else 'X'
    
    def check_winner(self):
        """Check if there is a winner."""
        # Rows, columns, diagonals
        winning_positions = [
            [0, 1, 2], [3, 4, 5], [6, 7, 8],  # Rows
            [0, 3, 6], [1, 4, 7], [2, 5, 8],  # Columns
            [0, 4, 8], [2, 4, 6]  # Diagonals
        ]
        
        for positions in winning_positions:
            values = [self.board[pos] for pos in positions]
            if values[0] == values[1] == values[2] and values[0] != '-':
                return values[0]
        
        return None  # No winner yet
    
    def is_draw(self):
        """Check if the game is a draw."""
        return all(cell != '-' for cell in self.board)
    
    def get_board_string(self):
        """Get the current board state as a string."""
        return ''.join(self.board)
    
    def get_legal_moves(self):
        """Get the positions of all legal moves."""
        return [i for i, cell in enumerate(self.board) if cell == '-']
    
    def pretty_print_board(self):
        """Pretty-print the board."""
        for i in range(0, 9, 3):
            print(f"{self.board[i]} | {self.board[i+1]} | {self.board[i+2]}")
            if i < 6:
                print("- "*5)

# Test the pretty_print_board method
tic_tac_toe = TicTacToe()
print("Initial board:")
tic_tac_toe.pretty_print_board()

# Make some moves
tic_tac_toe.make_move(0)
tic_tac_toe.make_move(4)
tic_tac_toe.make_move(8)
print("\nBoard after some moves:")
tic_tac_toe.pretty_print_board()

Initial board:
- | - | -
- - - - - 
- | - | -
- - - - - 
- | - | -

Board after some moves:
X | - | -
- - - - - 
- | O | -
- - - - - 
- | - | X