I have printed game rules at the beginning. I have prompted the user for choosing letter X (or x) or 0[zero]. It will be chosen randomly whether the user makes the first move or the computer in the first round. From subsequent rounds, user and computer will alternatively make first move. After each round screen would be cleared. I have set a sleep time of 1 sec while the computer makes its move. I have added two difficulty levels for the user: EASY (Enter e or E) and DIFFICULT (Enter d or D). In Easy mode, the computer makes moves randomly while in Hard mode, it uses the MiniMax algorithm. The board positions are numbered from 1 to 9.

Game Board Numbering

Error message is shown if the user enters an invalid choice in mode selection or inputting a number.