"The last method should be determineWinner which returns a 1 if player one won, a 2 if player 2 won, a 0 if it’s a ‘cat’s game’, and -1 if there is no winner yet and the game is not over."
You also need to implement a test class, TicTacToeTest, for your TicTacToe class. Make a few calls to playerMove() to make sure it works. Make at least one call to determineWinner() to make sure it works. Make at least one call to displayboard() to make sure it works."