sgtsquiggs · February 1, 2016 22:20 · Feb 1, 2016
diff --git a/game.py b/game.py
@@ -0,0 +1,176 @@
+import random
+
+
+def draw_board(board):
+    print('   |   |')
+    print(' %s | %s | %s' % (board[1], board[2], board[3]))
+    print('   |   |')
+    print('---+---+---')
+    print('   |   |')
+    print(' %s | %s | %s' % (board[4], board[5], board[6]))
+    print('   |   |')
+    print('---+---+---')
+    print('   |   |')
+    print(' %s | %s | %s' % (board[7], board[8], board[9]))
+    print('   |   |')
+
+
+def input_player_letter():
+    letter = ''
+    while not (letter == 'X' or letter == 'O'):
+        print('Choose X or O:')
+        letter = input().upper()
+
+    # the first element in the lsit is the player's letter
+    if letter == 'X':
+        return ['X', 'O']
+    else:
+        return ['O', 'X']
+
+
+def who_goes_first():
+    if random.randint(0, 1) == 0:
+        return 'computer'
+    else:
+        return 'player'
+
+
+def play_again():
+    print('Play again?')
+    return input().lower().startswith('y')
+
+
+def make_move(board, letter, move):
+    board[move] = letter
+
+
+def is_winner(board, letter):
+    return ((board[1] == board[2] == board[3] == letter) or
+            (board[4] == board[5] == board[6] == letter) or
+            (board[7] == board[8] == board[9] == letter) or
+            (board[1] == board[4] == board[7] == letter) or
+            (board[2] == board[5] == board[8] == letter) or
+            (board[3] == board[6] == board[9] == letter) or
+            (board[1] == board[5] == board[9] == letter) or
+            (board[7] == board[5] == board[3] == letter))
+
+
+def get_board_copy(board):
+    dupe_board = []
+
+    for i in board:
+        dupe_board.append(i)
+
+    return dupe_board
+
+
+def is_space_free(board, move):
+    return board[move] == ' '
+
+
+def get_player_move(board):
+    move = ' '
+    while move not in '1 2 3 4 5 6 7 8 9'.split() or not is_space_free(board, int(move)):
+        print('Move?')
+        move = input()
+    return int(move)
+
+
+def choose_random_move_from_list(board, moves_list):
+    possible_moves = []
+    for i in moves_list:
+        if is_space_free(board, i):
+            possible_moves.append(i)
+
+    if len(possible_moves) > 0:
+        return random.choice(possible_moves)
+    else:
+        return None
+
+
+def get_computer_move(board, computer_letter):
+    if computer_letter == 'X':
+        player_letter = 'O'
+    else:
+        player_letter = 'X'
+
+    # if this move wins the game for the computer
+    for i in range(1, 10):
+        copy = get_board_copy(board)
+        if is_space_free(copy, i):
+            make_move(copy, computer_letter, i)
+            if is_winner(copy, computer_letter):
+                return i
+
+    # if this move wins the game for the player
+    for i in range(1, 10):
+        copy = get_board_copy(board)
+        if is_space_free(copy, i):
+            make_move(copy, player_letter, i)
+            if is_winner(copy, player_letter):
+                return i
+
+    # random corner
+    move = choose_random_move_from_list(board, [1, 3, 7, 9])
+    if move is not None:
+        return move
+
+    # center
+    if is_space_free(board, 5):
+        return 5
+
+    # random side
+    move = choose_random_move_from_list(board, [2, 4, 6, 8])
+    if move is not None:
+        return move
+
+
+def is_board_full(board):
+    for i in range(1, 10):
+        if is_space_free(board, i):
+            return False
+    return True
+
+
+print('Welcome!')
+
+while True:
+    the_board = [' '] * 10
+
+    player_letter, computer_letter = input_player_letter()
+
+    turn = who_goes_first()
+    print('The', turn, 'will go first!')
+    game_is_playing = True
+
+    while game_is_playing:
+        if turn == 'player':
+            draw_board(the_board)
+            move = get_player_move(the_board)
+            make_move(the_board, player_letter, move)
+            if is_winner(the_board, player_letter):
+                draw_board(the_board)
+                print('YOU WIN!')
+                game_is_playing = False
+            elif is_board_full(the_board):
+                draw_board(the_board)
+                print('YOU TIE!')
+                break
+            else:
+                turn = 'computer'
+        else:
+            move = get_computer_move(the_board, computer_letter)
+            make_move(the_board, computer_letter, move)
+            if is_winner(the_board, computer_letter):
+                draw_board(the_board)
+                print('YOU LOSE!')
+                game_is_playing = False
+            elif is_board_full(the_board):
+                draw_board(the_board)
+                print('YOU TIE!')
+                break
+            else:
+                turn = 'player'
+
+    if not play_again():
+        break