REM tic tac toe
 GOSUB 1180:REM init
30 REM pre game settings
 FOR J=1 TO 9
 A(J)=32
 NEXT J
 FOR J=1 TO 5
 D(J)=0
 NEXT J
100 COUNT=0
110 R$=""
120 GOSUB 1070:REM print board
130 REM main cycle
140 GOSUB 540:REM machine move
 GOSUB 1070:REM PRINT BOARD
 GOSUB 870:REM win check
 IF R$<>""THEN 240
 GOSUB 980:REM human move
 GOSUB 1070:REM print board
 GOSUB 870:REM win check
210 IF R$="" THEN 140
 REM end main cycle
 REM
240 REM end of game
250 GOSUB 1070:REM print board
 REM
 IF R$="W" THEN PRINT "I WIN";:FLAG=-1
 IF R$="L" THEN PRINT "YOU WIN";:FLAG=1
 IF R$="D" THEN PRINT "DRAW";:FLAG=1
300 REM update knowledge base
310 FOR B=1 TO 5
320 FOR J=2 TO 9
 IF M(J)=D(B) THEN GOSUB 370
 NEXT J
350 NEXT B
360 GOTO 430
370 REM reorder elements in array
380 TEMP=M(J+FLAG)
390 M(J+FLAG)=M(J)
400 M(J)=TEMP
410 J=9
420 RETURN
430 REM
440 PRINT " - Updating priority   "
460 FOR J=1TO 9
 PRINT M(J);" ";
 NEXT J
490 PRINT
495 GOTO 30
500 INPUT "Press return to continue";A$
520 cls: GOTO 30
530 REM
540 REM machine move
550 P=ASC("O")
560 X=0
570 J=1
580 IF A(W(J))=A(W(J+1)) AND A(W(J+2))=32 AND A(W(J))=P THEN X=W(J+2):GOTO 750
590 IF A(W(J))=A(W(J+2)) AND A(W(J+1))=32 AND A(W(J))=P THEN X=W(J+1):GOTO 750
600 IF A(W(J+1))=A(W(J+2)) AND A(W(J))=32 AND A(W(J+1))=P THEN X=W(J):GOTO 750
610 IF J<21 THEN J=J+3:GOTO 580
620 IF P=ASC("O") THEN P=ASC("X"):GOTO 570
630 REM if no win/block move found
640 REM then this next section used
650 J=1
660 IF A(M(J))=32 THEN X=M(J):GOTO 750
670 IF J<10 THEN J=J+1:GOTO 660
680 H=0
690 H=H+1
700 X=INT(RND(1)*9):IF A(X)=32 THEN 750
710 IF H<100 THEN 690
720 R$="D":REM draw
730 RETURN
740 REM
750 REM make move
760 A(X)=ASC("O")
770 COUNT=COUNT+1
780 D(COUNT)=X
790 FLAG=0
800 FOR J=1 TO 9
810 IF A(J)=32 THEN FLAG =1
820 NEXT J
830 IF FLAG =0 AND R$="" THEN R$="D"
840 REM if all positions filled, and r$ not assigned, draw
850 RETURN
860 REM
870 REM win check
880 J=1
890 IF A(W(J))=32 THEN J=J+3:IF J<22 THEN GOTO 890
900 IF J>23 THEN RETURN
910 IF A(W(J))=A(W(J+1)) AND A(W(J))=A(W(J+2)) THEN 940
920 IF J<22 THEN J=J+3:GOTO 890
930 RETURN
940 IF A(W(J))=ASC("O") THEN R$="W"
950 IF A(W(J))=ASC("X") THEN R$="L"
960 RETURN
970 REM
980 REM human move
990 REM
1000 PRINT
1010 ' INPUT "Enter move ";MOVE
1015 MOVE = RAND(9)
1020 IF MOVE<1 OR MOVE >9 THEN 1010
1030 IF A(MOVE)<>32 THEN 1010
1040 A(MOVE)=ASC("X")
1050 RETURN
1060 REM
1070 REM print board
1080 locate 1,1 : 'PRINT@0,"";
 PRINT " 7 ! 8 ! 9   ";CHR$(A(7));" ! ";CHR$(A(8));" ! ";CHR$(A(9))
 PRINT "---+---+--- ---+---+---"
 PRINT " 4 ! 5 ! 6   ";CHR$(A(4));" ! ";CHR$(A(5));" ! ";CHR$(A(6))
 PRINT "---+---+--- ---+---+---"
 PRINT " 1 ! 2 ! 3   ";CHR$(A(1));" ! ";CHR$(A(2));" ! ";CHR$(A(3))
 REM
 REM
 RETURN
1180 REM init
 CLS
 DIM A(9):REM board
 DIM M(10):REM hold knowledge
 DIM W(24):REM win/block data
 DIM D(5):REM moves
 REM win/block data
 FOR J=1 TO 24
 READ W(J)
 NEXT J
1280 DATA 1,2,3,4,5,6,7,8,9
1290 DATA 1,4,7,2,5,8,3,6,9
1300 DATA 1,5,9,3,5,7
1310 REM init knowledge base
1320 FOR J=1 TO 10
 READ M(J)
 NEXT J
1350 DATA 2,6,8,4,7,3,1,9,5,2
 RETURN