Question

write a program for python 3
write the functions that could be used in an implementation of the game tic-tac-toe. Below are the definitions of the different functions. The code to test each function is currently in the main() of the lab10.py file.
• A function to build the board. This method should create a list of the numbers 1 – 9 and return that list. build_board () -> list
• A void function to display the board. (see the sample displays in Part II)
display_board( list ) -> void
• A Boolean method to determine if a spot is a legal spot on the board.
is_legal ( board, spot ) -> bool
• A void method to fill a spot on the board. This method will need to have the board, the position to be filled and the character to place in that position. Make sure that the spot is legal using the function above before you fill the spot.
fill_spot ( board, spot, char ) -> void
• A Boolean method to determine if the game has been won.
is_game_won ( board ) -> bool
• A Boolean method to determine if the game is over. This should call the previously mentioned method plus check to make sure there are more plays allowed on the board.
is_game_over ( board, num_plays ) -> bool
The following is the additional function required for the assignment.   
• A function play_game()to play the game. This function should continue as long as the game is not over. Once the game is over, display the message “Player 1 wins!”, “Player 2 wins”, or “Tie” as is appropriate.     

Once your basic functions are working: Rewrite play_game(), your game should do the following:
• If a player plays ‘o’ or ‘x’ in spot which is already played, show message “Please check the valid spot’ at the bottom of the window,   until the player click the empty (valid) spot. (Fig 4 shows that player 2 try to play ‘o’ on position 5 or 1 or 7)
• When game is over, show message about the winner or ‘nobody wins’. Part IV (Optional) Repeat the game When the game finishes, allow user to choose whether to play again.

Answer 1

'''
Python version : 3.6
Python program to allow the user to play the game of tic tac toe
'''

# function that create a list of the numbers 1 – 9 and return that list
def build_board():
  
   board = []
  
   for i in range(1,10):
       board.append(i)
      
   return board

# function to display the board  
def display_board(list):
  
   board = ""
   for i in range(0,len(list),3):
      
       for j in range(3):
           board += str(list[i+j])+"| "
       board += "\n"

   print(board)

# function to return if the spot is legal or not  
def is_legal( board, spot ):
  
   if(spot >= 1 and spot <= 9 and (board[spot-1] == spot)):
       return True
      
   return False

# function to fill the spot with the given char  
def fill_spot( board, spot, char ):
  
   board[spot-1] = char

# function to check and return if the game is won by wither of the two players or not  
def is_game_won( board ) :
  
   # check row-wise  
   for i in range(0,len(board),3):  
       if( board[i] == board[i+1] == board[i+2]):
          
           if(board[i] == 'x' or board[i] == 'o'):
               return True
  
   #check column-wise
   for i in range(0,3):
      
       if(board[i] == board[i+3] == board[i+6]):
          
           if board[i] == 'x' or board[i] == 'o':
               return True
  
   # check main diagonal
   if(board[0] == board[4] == board[8]):
       if board[4] == 'o' or board[i] == 'x' :
           return True
          
   # check other diagonal
   if(board[2] == board[4] == board[6]):
       if board[4] == 'o' or board[4] == 'x':
           return True

   return False

# function to return if the game is over or not  
def is_game_over( board, num_plays ) :
   if(is_game_won(board) or num_plays == len(board)):  
       return True
   return False

# function to play game  
def play_game():
  
   choice = 'y'
   # loop continues till the user wants
   while choice.lower() == 'y':
  
       player = 'x'
       num_plays = 0
       board = build_board()
       display_board(board)
       # loop continues till this game is not over
       while not is_game_over(board, num_plays):
           num_plays += 1
           print('Player %s turn : '%player)
           spot = int(input('Enter a spot(1-9) : '))
          
           while(not is_legal(board,spot)):
               print("Please check the valid spot at the bottom of the window")
               spot = int(input('Enter a spot(1-9) : '))
              
           fill_spot(board,spot,player)
           display_board(board)
           if is_game_won(board):
               break
              
           if player == 'x':
               player = 'o'
           else:
               player = 'x'
      
       if(is_game_won(board)):
           if player == 'x':
               print('Player 1 wins!')
           else:
               print('Player 2 wins!')
              
       else:
           print('Tie')
      
       choice = input('Do you want to continue ? (y/n) ')

#call play_game function      
play_game()      
#end of program      

Code Screenshot:

Output: