100 REM TIC-TAC-TOE. YOU (X) VS. THE COMPUTER (O)
110 GOTO 200
120 BOARD IS IN MEMORY LOCATIONS 0007-000F
130 .  0 IS EMPTY, 1 IS X. 3 TS O
140 I HAS CURRENT POSITION
150 G IS PEEK ROUTINE ADDRESS
160 P IS POKE ROUTINE ADDRESS
170 F=1 IF YOU PLAY FIRST
180 U IS NUMBER OF UNPLAYED SQUARES
190 Z=1 IF SOMEONE WON
200 REM
210 ?"TOM PITTMAN'S ";
211 ?"TIC-TAC-TOE."
212 ?"YOU AGAINST";
213 ?" TINY BASIC"
221 ?"YOU ARE X. I AM";
222 ?" O. YOU"
231 ?"PLAY YOUR";
232 ?" TURN BY TYPING"
233 ?"THE NUMBER OF A";
234 ?" SQUARE."
240 A=0
250 B=0
260 C=0
270 D=0
280 E=0
290 F=0
441 GOTO 500
450 TO CONSERVE MEMORY, LINES 100-500 MAY BE RUN ONCE
460 THEN DELETED (CLEAR) BEFORE LOADING THE REST OF THE PROGRAM
500 REM---ON WITH THE SHOW...
1000 LET F=1
1010 PRINT
1020 PRINT "NEW GAME."
1100 LET I=7
1110'
1111 A(I)=0:I=I+1
1120 IF I<16 GOTO 1110
1130 LET U=9
1140 LET Z=0
1151 IF F=0 GOTO 4010
1161 GOTO 2010
1500 REM X WON.
1510 LET Z=1
1520 LET F=0
2000 REM PRINT GAME STATE
2010 LET I=6
2110 LET I=I+1
2120 PRINT " ";
2131 GOTO A(I)*20+2200
2200 PRINT I-6;
2210 GOTO 2300
2220 PRINT "X";
2230 GOTO 2300
2260 PRINT "O";
2300 IF I/3*3=I GOTO 2400
2310 PRINT " |";
2320 GOTO 2110
2400 PRINT
2420 IF I=15 GOTO 3000
2430 PRINT "---+---+---"
2440 GOTO 2110
3000 IF Z=0 GOTO 3100
3010 REM THE GAME IS OVER.
3020 IF F=1 GOTO 3050
3030 PRINT "YOU WIN."
3040 GOTO 1010
3050 PRINT "I WIN."
3060 GOTO 1010
3100 IF U>0 GOTO 3210
3110 PRINT "CAT'S GAME."
3120 LET F=1-F
3130 GOTO 1010
3200 REM INPUT NEXT PLAY.
3210'
3211 PRINT "YOUR PLA";
3223 INPUT Y:I=Y
3231 IF I<=0 GOTO 3240
3232 IF I<10 GOTO 3270
3240'
3241 ?"PLEASE TYPE A";
3242 ?" NUMBER"
3243 ?"BETWEEN 1 AND 9";
3251 ?" WHERE YOU"
3252 ?"WISH TO PLAY";
3253 ?" YOUR X"
3260 GOTO 3210
3270'
3271 IF A(I+6)=0 GOTO3310
3281 ?"THAT SQUARE IS";
3282 ?" ALREADY":?"TAKEN"
3290 GOTO 3210
3300 REM CHECK IF X WON.
3310'
3311 A(I+6)=1:U=U-1
3320 LET W=6100
3330 GOSUB W
3341 IF J<=0 GOTO 3350
3342 IF L*M*N=1 GOTO 1510
3350 LET W=W+100
3360 IF W<6500 GOTO 3330
3400 REM CHECK IF CATS GAME
3410 IF U=0 GOTO 2010
4000 REM FIND BEST O PLAY
4010 LET I=1
4020 LET T=-1
4290 REM EVALUATE I'TH SQUARE
4300 LET S=0
4311 IF A(I+6)>0 GOTO4480
4320 LET W=6100
4330 GOSUB W
4340 IF J=0 GOTO 4410
4350 LET J=L+M+N
4361 IF J=4 GOTO 4410
4371 IF J=2 S=S+20
4381 IF J=6 S=S+100
4391 IF J=0 S=S+2
4400 LET S=S+J
4410 LET W=W+100
4420 IF W<6500 GOTO 4330
4431 IF S<T GOTO 4470
4440 LET T=S
4450 LET B=I
4460 REM SAY SOMETHING, SO IT WONT SEEN SO LONG.
4470 PRINT ".";
4480 LET I=I+1
4490 IF I<10 GOTO 4300
4500 PRINT "I PLAY ";B
4510 PRINT
4521 A(B+6)=3
4530 LET U=U-1
4541 IF T<100 GOTO 2010
4550 REM I WON I WON I WON
4560 F=1
4570 Z=1
4580 GOTO 2010
6000 REM SUBROUTINE TO LOOK AT ONE ROW, COL, OR DIAG
6010 REM I IS THE POSITION OF REFERENCE
6020 REM L,M,N ARE RETURNED WITH CONTENTS OF THE THREE SQUARES
6030 REM ENTER AT 6100,6200,6300, OR 6400...
6040 REM TO EXAMINE ROW,COLUMN,DOWN DIAGONAL OR UP DIAGONAL
6090 REM W=HORIZONTAL
6100 LET J=(I-1)/3*3+8
6110 LET D=1
6120 GOTO 6500
6190 REM W=VERTICAL
6200 LET J=I-(I-1)/3*3+9
6210 LET D=3
6220 GOTO 6500
6290 REM W=DOWN DIAGONAL
6300'
6301 IF I%4<>1 GOTO6440
6310 LET D=4
6320 REM BOTH DIAGONALS GO THRU CENTER
6330 LET J=11
6340 GOTO 6500
6390 REM W=UP DIAGONAL
6400 LET D=2
6411 IF I<=1 GOTO 6430
6412 IF I>=9 GOTO 6430
6413 IF I%2=1 GOTO 6330
6430 REM A DIAGONAL DOES NOT GO THRU THIS SQUARE
6440 LET J=0
6450 RETURN
6490 REM NOW WE KNOW CENTER OF THIS THREE AND +/- OFFSET
6500'
6502 L=A(J-D)
6511 M=A(J)
6521 N=A(J+D)
6530 RETURN