DECLARE FUNCTION chwin! (a!, p!)
DECLARE FUNCTION move! (a!, p!)

sta:
DO
won = 0
CLS
PRINT "1|2|3"
PRINT "-----"
PRINT "4|5|6"
PRINT "-----"
PRINT "7|8|9"
RANDOMIZE TIMER
DIM SHARED sp(9) AS INTEGER
FOR a = 1 TO 9
sp(a) = 0
NEXT
reg = INT(RND * 2)
fturn = INT(RND * 2)
IF fturn = 1 THEN
 IF reg = 1 THEN
 n = move(5, 1)
 FOR a = 1 TO 9
  IF sp(a) = 2 THEN t = a
 NEXT
 IF t = 2 THEN
  n = move(3, 1)
  n = move(7, 1)
  n = move(6, 1)
  n = move(9, 1)
  n = move(4, 1)
 END IF
 IF t = 4 THEN
  n = move(1, 1)
  IF move(9, 1) THEN n = move(2, 1)
  IF move(8, 1) THEN n = move(3, 1)
 END IF
 IF t = 6 THEN
  n = move(9, 1)
  IF move(1, 1) THEN n = move(8, 1)
  IF move(7, 1) THEN n = move(2, 1)
 END IF
 IF t = 8 THEN
  n = move(7, 1)
  IF move(3, 1) THEN n = move(4, 1)
  IF move(1, 1) THEN n = move(6, 1)
 END IF
 IF t = 1 THEN
  n = move(7, 1)
  n = move(3, 1)
  n = move(2, 1)
  n = move(8, 1)
  n = move(6, 1)
  n = move(4, 1)
  IF won = 0 THEN LOCATE 10: PRINT "Tie!"
 END IF
 IF t = 3 THEN
  n = move(9, 1)
  n = move(1, 1)
  n = move(2, 1)
  n = move(8, 1)
  n = move(4, 1)
  n = move(6, 1)
  IF won = 0 THEN LOCATE 10: PRINT "Tie!"
 END IF
 IF t = 7 THEN
  n = move(1, 1)
  n = move(9, 1)
  n = move(8, 1)
  n = move(2, 1)
  n = move(6, 1)
  n = move(4, 1)
  IF won = 0 THEN LOCATE 10: PRINT "Tie!"
 END IF
 IF t = 9 THEN
  n = move(3, 1)
  n = move(7, 1)
  n = move(8, 1)
  n = move(2, 1)
  n = move(4, 1)
  n = move(6, 1)
  IF won = 0 THEN LOCATE 10: PRINT "Tie!"
 END IF
 ELSE
  n = move(3, 1)
  IF sp(2) = 2 THEN
   n = move(5, 1)
   n = move(7, 1)
   n = move(6, 1)
   n = move(9, 1)
   n = move(4, 1)
  ELSEIF sp(4) = 2 THEN
   n = move(5, 1)
   n = move(9, 1)
   n = move(1, 1)
   n = move(2, 1)
   n = move(9, 1)
  ELSEIF sp(6) = 2 THEN
   n = move(5, 1)
   n = move(7, 1)
   n = move(2, 1)
   n = move(1, 1)
   n = move(8, 1)
  ELSEIF sp(8) = 2 THEN
   n = move(5, 1)
   n = move(7, 1)
   n = move(9, 1)
   n = move(1, 1)
   n = move(6, 1)
  ELSEIF sp(7) = 2 THEN
   n = move(1, 1)
   n = move(2, 1)
   n = move(9, 1)
   n = move(5, 1)
   n = move(6, 1)
  ELSE
   n = move(7, 1)
   n = move(5, 1)
   IF sp(1) = 2 THEN
    n = move(9, 1)
    n = move(6, 1)
    n = move(8, 1)
   ELSEIF sp(9) = 2 THEN
    n = move(1, 1)
    n = move(4, 1)
    n = move(2, 1)
   ELSEIF sp(2) = 2 THEN
    n = move(8, 1)
    n = move(9, 1)
    n = move(1, 1)
    n = move(4, 1)
    'n = move(6, 1)
    IF won = 0 THEN LOCATE 10: PRINT "Tie!"
   ELSEIF sp(4) = 2 THEN
    n = move(6, 1)
    n = move(9, 1)
    n = move(1, 1)
    n = move(2, 1)
    IF won = 0 THEN LOCATE 10: PRINT "Tie!"
   ELSEIF sp(6) = 2 THEN
    n = move(6, 1)
    n = move(9, 1)
    n = move(1, 1)
    n = move(2, 1)
    IF won = 0 THEN LOCATE 10: PRINT "Tie!"
   ELSE
    n = move(2, 1)
    n = move(1, 1)
    n = move(9, 1)
    x = move(6, 1)
    IF won = 0 THEN LOCATE 10: PRINT "Tie!"
   END IF
  END IF
 END IF
ELSE
 a = -1
 WHILE a
  LOCATE 9: INPUT "Move to where:", m
  a = move(m, 2)
 WEND
 IF move(5, 1) THEN
  a = INT(RND * 5)
  n = move(a * 2 + 1, 1)
   q = 0
   f = m
   m = 0
   DO
    m = 0
    FOR a = 1 TO 9
     IF (chwin(a, 2) = 1) AND (sp(a) = 0) THEN m = a
    NEXT
    FOR a = 1 TO 9
     IF (chwin(a, 1) = 1) AND (sp(a) = 0) THEN m = a
    NEXT
    IF m > 0 THEN
     n = move(m, 1)
    ELSE
     'IF sp(10 - f) = 2 THEN
      'PRINT m
      'PRINT "a"
     ' n = move(4, 1)
     ' n = move(6, 1)
    ' ELSE
      'PRINT "b"
      IF move(1, 1) THEN
       IF move(3, 1) THEN
        IF move(7, 1) THEN
         IF move(9, 1) THEN
          IF move(2, 1) THEN
           IF move(4, 1) THEN
            IF move(6, 1) THEN
             n = move(8, 1)
            END IF
           END IF
          END IF
         END IF
        END IF
       END IF
      END IF
     END IF
    'END IF
    q = 1
    FOR a = 1 TO 9
     IF sp(a) = 0 THEN q = 0
    NEXT
   LOOP WHILE won = 0 AND q = 0
   IF won = 0 THEN LOCATE 10: PRINT "Tie!"

 ELSE
  IF (m MOD 2) = 1 THEN
   q = 0
   f = m
   m = 0
   DO
    m = 0
    FOR a = 1 TO 9
     IF (chwin(a, 2) = 1) AND (sp(a) = 0) THEN m = a
    NEXT
    FOR a = 1 TO 9
     IF (chwin(a, 1) = 1) AND (sp(a) = 0) THEN m = a
    NEXT
    IF m > 0 THEN
     n = move(m, 1)
    ELSE
     IF sp(10 - f) = 2 THEN
      'PRINT m
      'PRINT "a"
      n = move(4, 1)
      n = move(6, 1)
     ELSE
      'PRINT "b"
      IF move(1, 1) THEN
       IF move(3, 1) THEN
        IF move(7, 1) THEN
         IF move(9, 1) THEN
          IF move(2, 1) THEN
           IF move(4, 1) THEN
            IF move(6, 1) THEN
             n = move(8, 1)
            END IF
           END IF
          END IF
         END IF
        END IF
       END IF
      END IF
     END IF
    END IF
    q = 1
    FOR a = 1 TO 9
     IF sp(a) = 0 THEN q = 0
    NEXT
   LOOP WHILE won = 0 AND q = 0
   IF won = 0 THEN LOCATE 10: PRINT "Tie!"
  ELSE
   q = 0
   f = m
   m = 0
   z = 1
   DO
    m = 0
    FOR a = 1 TO 9
     IF (chwin(a, 2) = 1) AND (sp(a) = 0) THEN m = a
    NEXT
    FOR a = 1 TO 9
     IF (chwin(a, 1) = 1) AND (sp(a) = 0) THEN m = a
    NEXT
    IF m > 0 THEN
     n = move(m, 1)
    ELSE
     IF (sp(2) = 2) AND (sp(4) = 2) AND (sp(1) = 0) THEN
      n = move(1, 1)
     ELSEIF (sp(2) = 2) AND (sp(6) = 2) AND (sp(3) = 0) THEN
      n = move(3, 1)
     ELSEIF (sp(8) = 2) AND (sp(4) = 2) AND (sp(7) = 0) THEN
      n = move(7, 1)
     ELSEIF (sp(8) = 2) AND (sp(6) = 2) AND (sp(9) = 0) THEN
      n = move(9, 1)
     ELSE
      'PRINT "b"
      IF move(1, 1) THEN
       IF move(3, 1) THEN
        IF move(7, 1) THEN
         IF move(9, 1) THEN
          IF move(2, 1) THEN
           IF move(4, 1) THEN
            IF move(6, 1) THEN
             n = move(8, 1)
            END IF
           END IF
          END IF
         END IF
        END IF
       END IF
      END IF
     END IF
    END IF
    q = 1
    FOR a = 1 TO 9
     IF sp(a) = 0 THEN q = 0
    NEXT
   LOOP WHILE won = 0 AND q = 0
   IF won = 0 THEN LOCATE 10: PRINT "Tie!"
   
  END IF
 END IF
END IF
LOCATE 11: PRINT "Play Again?"
k$ = INPUT$(1)
LOOP WHILE UCASE$(k$) = "Y"

FUNCTION chwin (a, p)
n = 0
IF (a < 4) THEN
 IF (sp(a + 3) = p) AND (sp(a + 6) = p) THEN n = 1
ELSEIF (a < 7) THEN
 IF (sp(a - 3) = p) AND (sp(a + 3) = p) THEN n = 1
ELSEIF (sp(a - 6) = p) AND (sp(a - 3) = p) THEN n = 1
END IF
IF ((a MOD 3) = 1) THEN
 IF (sp(a + 1) = p) AND (sp(a + 2) = p) THEN n = 1
ELSEIF ((a MOD 3) = 2) THEN
 IF (sp(a - 1) = p) AND (sp(a + 1) = p) THEN n = 1
ELSEIF (sp(a - 2) = p) AND (sp(a - 1) = p) THEN n = 1
END IF
IF a = 1 THEN
 IF (sp(5) = p) AND (sp(9) = p) THEN n = 1
ELSEIF a = 5 THEN
 IF (sp(1) = p) AND (sp(9) = p) THEN n = 1
 IF (sp(3) = p) AND (sp(7) = p) THEN n = 1
ELSEIF a = 9 THEN
 IF (sp(1) = p) AND (sp(5) = p) THEN n = 1
ELSEIF a = 3 THEN
 IF (sp(5) = p) AND (sp(7) = p) THEN n = 1
ELSEIF a = 7 THEN
 IF (sp(3) = p) AND (sp(5) = p) THEN n = 1
END IF
chwin = n
END FUNCTION

FUNCTION move (a, p)
SHARED won
IF won = 0 THEN
IF (a < 1) OR (a > 9) THEN
 move = -1
 EXIT FUNCTION
END IF
IF sp(a) = 0 THEN
 sp(a) = p
ELSE
 move = -1
 EXIT FUNCTION
END IF

y = INT((a - 1) / 3) * 2 + 1
x = ((a - 1) MOD 3) * 2 + 1
 LOCATE y, x
 IF p = 1 THEN PRINT "X"
 IF p = 2 THEN PRINT "O"

IF p = 1 THEN LOCATE 8: PRINT "Computers move:"; a
IF chwin(a, p) = 1 THEN
 won = 1
 LOCATE 10
 IF p = 1 THEN PRINT "Computer won!"
 IF p = 2 THEN PRINT "Person won!"
 'PRINT "Play Again?"
 'f$ = UCASE$(INPUT$(1))
 'IF f$ = "Y" THEN CHAIN "tic.bas"
 'END
 move = 0
 EXIT FUNCTION
END IF

IF p = 1 THEN
 a = -1
 WHILE a
  LOCATE 9: PRINT SPACE$(20)
  LOCATE 9: INPUT "Move to where: ", m
  a = move(m, 2)
 WEND
END IF
END IF
move = 0
END FUNCTION