DIM WIN_PATTERNS(8, 3)
WIN_PATTERNS = ((1, 2, 3), (4, 5, 6), (7, 8, 9), (1, 4, 7), (2, 5, 8), (3, 6, 9), (1, 5, 9),(3, 5, 7))
 

DATA 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 4, 7, 2, 5, 8, 3, 6, 9, 1, 5, 9,3, 5, 7

DIM WIN_PATTERNS(7,2)= (1,2,3,4,5,6,7,8,9,1,4,7,2,5,8,3,6,9,1,5,9,3,5,7)
for i=0 to 2:for j=0 to 7:?WIN_PATTERNS(j,i):next j:next i

OPTION BASE 1

' Display the game title
PRINT TAB(30); "TIC-TAC-TOE"
PRINT TAB(15); " "
PRINT: PRINT: PRINT


' Initialize the game board and the optimal moves sequence
DIM S(9)
DIM MOVES(9) = (5, 1, 3, 7, 9, 2, 4, 6, 8)

' Ask the player to choose their symbol
INPUT "DO YOU WANT 'X' OR 'O'", PLAYER_CHOICE$
IF PLAYER_CHOICE$ = "X" THEN
   P$ = "X"
   Q$ = "O"
ELSE
   P$ = "O"
   Q$ = "X"
END IF

' Print the current state of the game board
SUB PRINT_BOARD
   PRINT " 1 | 2 | 3 "
   PRINT "---+---+---"
   PRINT " 4 | 5 | 6 "
   PRINT "---+---+---"
   PRINT " 7 | 8 | 9 "
   PRINT
   FOR I = 1 TO 9 STEP 3
       FOR J = 0 TO 2
           CELL = I + J
           ' Determine the mark to print based on the cell's state
           IF S(CELL) = 1 THEN
               MARK$ = " " + P$ + " "
           ELSEIF S(CELL) = -1 THEN
               MARK$ = " " + Q$ + " "
           ELSE
               MARK$ = "   "
           END IF
           
           ' Print the cell's content
           IF J < 2 THEN
               PRINT MARK$; "|";
           ELSE
               PRINT MARK$
           END IF
       NEXT J
       ' Print the row separator unless it's the last row
       IF I < 7 THEN PRINT "---+---+---"
   NEXT I
   PRINT: PRINT: PRINT
END SUB

' Initialize the winning patterns
DIM WIN_PATTERNS(8, 3)
DATA 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 4, 7, 2, 5, 8, 3, 6, 9, 1, 5, 9, 3, 5, 7
FOR I = 1 TO 8
   FOR J = 1 TO 3
       READ WIN_PATTERNS(I, J)
   NEXT J
NEXT I

' Check if there's a win, a draw, or if the game should continue
FUNCTION CHECK_WIN()
   FOR I = 1 TO 8
       ' Check for a winning pattern
       IF S(WIN_PATTERNS(I, 1)) <> 0 AND S(WIN_PATTERNS(I, 1)) = S(WIN_PATTERNS(I, 2)) AND S(WIN_PATTERNS(I, 2)) = S(WIN_PATTERNS(I, 3)) THEN
           CHECK_WIN = S(WIN_PATTERNS(I, 1))
           EXIT FUNCTION
       END IF
   NEXT
   
   ' Check for any empty cell to continue the game
   FOR J = 1 TO 9
       IF S(J) = 0 THEN
           CHECK_WIN = 2 ' Game continues
           EXIT FUNCTION
       END IF
   NEXT
   
   ' If no win and no empty cells, it's a draw
   CHECK_WIN = 0
END FUNCTION

' Determine the computer's move based on a predefined sequence
SUB COMPUTER_MOVE
   FOR I = 1 TO 9
       IF S(MOVES(I)) = 0 THEN
           S(MOVES(I)) = -1
           EXIT SUB
       END IF
   NEXT
END SUB

' Main game loop
DO
   ' Print the board and ask for the player's move
   PRINT_BOARD
   DO
       INPUT "WHERE DO YOU MOVE (1-9, 0 to quit): ", M
       IF M = 0 THEN
           PRINT "THANKS FOR THE GAME."
           EXIT DO
       ELSEIF M >= 1 AND M <= 9 AND S(M) = 0 THEN
           S(M) = 1 ' Mark the player's move
           EXIT DO
       ELSE
           PRINT "THAT SQUARE IS OCCUPIED OR INVALID."
       END IF
   LOOP
   
   ' Check the game state after the player's move
   IF CHECK_WIN() <> 2 THEN EXIT DO
   
   ' Computer makes its move
   COMPUTER_MOVE
   
   ' Check the game state after the computer's move
   IF CHECK_WIN() <> 2 THEN EXIT DO
LOOP

' Final board print and game result announcement
PRINT_BOARD
SELECT CASE CHECK_WIN()
   CASE 1
       PRINT "CONGRATULATIONS! YOU WIN!"
   CASE -1
       PRINT "COMPUTER WINS! TRY AGAIN."
   CASE 0
       PRINT "IT'S A DRAW!"
END SELECT