;; Define the initial game state, where each square is represented by a number

(define initial-board '(0 1 2 3 4 5 6 7 8))

​

;; Define a function to display the game board

(define (display-board board)

  (display "\n")

  (display (string-append " " (number->string (car board)) " | " (number->string (cadr board)) " | " (number->string (caddr board)) "\n"))

  (display "---+---+---\n")

  (display (string-append " " (number->string (cadddr board)) " | " (number->string (caddddr board)) " | " (number->string (car (cdr (cdr (cdr (cdr board)))))) "\n"))

  (display "\n"))

​

;; Define a function to check if a player has won

(define (check-win player board)

  (or

   (and (= (car board) player) (= (cadr board) player) (= (caddr board) player))

   (and (= (cadddr board) player) (= (caddddr board) player) (= (car (cdr (cdr (cdr (cdr board)))))))

   (and (= (car board) player) (= (cadddr board) player) (= (car (cdr (cdr (cdr (cdr board)))))))

   (and (= (caddr board) player) (= (caddddr board) player) (= (car (cdr (cdr (cdr (cdr board)))))))

   (and (= (car board) player) (= (caddddr board) player) (= (car (cdr (cdr (cdr board))))))))

​

;; Define a function to check if the game is a tie

(define (check-tie board)

  (not (member 0 board)))

​

;; Define a function to get the player's move

(define (get-move player board)

  (display (string-append "\nPlayer " (number->string player) ", enter your move (0-8): "))

  (let ((move (read)))

    (cond

     ((not (integer? move)) (display "Invalid input, please enter a number from 0 to 8.") (get-move player board))

     ((< move 0) (display "Invalid move, please enter a number from 0 to 8.") (get-move player board))

     ((> move 8) (display "Invalid move, please enter a number from 0 to 8.") (get-move player board))

     ((not (zero? (list-ref board move))) (display "Invalid move, that square is already taken.") (get-move player board))

     (else (list-set board move player)))))

​

​

;; Define the main game loop

(define (game-loop player board)

  (display-board board)

  (cond

   ((check-win player board) (display (string-append "\nPlayer " (number->string player) " wins!\n")))

   ((check-tie board) (display "\nIt's a tie!\n"))

   (else (game-loop (if (= player 1) 2 1) (get-move player board)))))

​

​

;; Start the game

(display "Welcome to Tic Tac Toe!\n\n")

(game-loop 1 initial-board)