10 REM CHECK.ECB
   15 PRINT "I CAN PLAY CHECKERS WITH YOU. I AM X."
   20 PRINT "AND YOU ARE O. THE COMPUTER WILL GO FIRST,-NOTE:  SQUARES"
   30 PRINT "ARE IN THE FORM-(X,Y) AND SQ. 1,1 IS THE BOTTOM LEFT!"
   40 PRINT "DO NOT ATTEMPT A DOUBLE JUMP ON YOUR PIECE MIGHT JUST "
   50 PRINT "DISAPPEAR(SAME FOR A TRIPLE!)"
   60 PRINT "    WAIT FOR THE COMP. TO MOVE!!!!!"
   70 LET G=-1
   75 LET L=-1
   80 DIM R(50),M(50)
   85 REM&I&IODD(X)
   90 DEF FND(X)=X-2*INT(X/2)
  100 DIM S(10,10)
  110 DATA 1,0,1,0,0,0,-1,0,0,1,0,0,0,-1,0,-1,15
  120 FOR X=1 TO 8
  130   FOR Y=1 TO 8
  140     READ J
  150     IF J=15 THEN 180
  160     LET S(X,Y)=J
  170     GOTO 200
  180     RESTORE
  190     READ S(X,Y)
  200   NEXT Y
  210 NEXT X
  220 REM
  225 LET L=1
  230 REM
  240 FOR X2=1 TO 8
  250   FOR Y2=1 TO 8
  255     LET S9=S(X2,Y2)
  260     IF S9>=0 THEN 380
  310     IF S9=-2 THEN 340
  320     GOSUB 430
  330     GOTO 380
  340     GOSUB 650
  380   NEXT Y2
  390 NEXT X2
  393 IF L=1 THEN 400
  396 RETURN
  400 PRINT
  410 GOSUB 1140
  420 GOTO 220
  430 REM
  435 LET U=X2-1
  450 IF U<1 THEN 540
  460 REM
  470 LET V=Y2-1
  480 IF V<1 THEN 625
  485 IF S(U,V)<>0 THEN 500
  490 GOSUB 910
  500 IF S(U,V)<=0 THEN 540
  505 LET U=X2-2
  507 IF U<1 THEN 540
  510 LET V=V-1
  520 IF V<1 THEN 540
  525 IF S(U,V)<>0 THEN 540
  530 GOSUB 910
  540 REM
  550 LET U=X2+1
  560 IF U>8 THEN 630
  570 REM
  580 LET V=Y2-1
  583 IF V<1 THEN 630
  587 IF S(U,V)<>0 THEN 600
  590 GOSUB 910
  600 IF S(U,V)<=0 THEN 630
  605 LET U=X2+2
  607 IF U>8 THEN 630
  610 LET V=V-1
  615 IF V<1 THEN 630
  617 IF S(U,V)<>0 THEN 630
  620 GOSUB 910
  625 REMWHERE DID I GO ??
  630 RETURN
  650 REMKING MOVES
  660 FOR A=-1 TO 1 STEP 2
  670   FOR B=-1 TO 1 STEP 2
  680     LET U=X2+A
  690     LET V=Y2+B
  700     IF U<1 THEN 870
  710     IF U>8 THEN 870
  720     IF V<1 THEN 870
  730     IF V>8 THEN 870
  740     IF S(U,V)<>0 THEN 770
  750     GOSUB 910
  760     GOTO 870
  770     IF S(U,V)=G THEN 870
  780     IF S(U,V)=2*G THEN 870
  790     LET U=U+A
  810     IF U<1 THEN 870
  820     IF U>8 THEN 870
  830     IF V<1 THEN 870
  840     IF V>8 THEN 870
  850     IF S(U,V)<>0 THEN 870
  860     GOSUB 910
  870   NEXT B
  880 NEXT A
  890 RETURN
  900 REM
  910 REM&I&IEVAL. SECTION
  920 LET P=P+1
  940 IF V<>1 THEN 960
  950 LET Q=Q+2
  960 IF V<>8 THEN 980
  970 LET Q=Q-2
  980 REM
  990 IF U<>1 THEN 1010
 1000 LET Q=Q+1
 1010 IF U<>8 THEN 1030
 1020 LET Q=Q+1
 1030 FOR C=-1 TO 1 STEP 2
 1033   IF U+C<1 THEN 1060
 1037   IF U+C>8 THEN 1060
 1040   IF S(U+C,V+G)<1 THEN 1060
 1050   LET Q=Q-1
 1060   REM
 1062   IF U-C>8 THEN 1100
 1063   IF U-C<1 THEN 1100
 1064   IF S(U-C,V-G)<1 THEN 1080
 1070   LET Q=Q+5
 1080   REM
 1090   REM
 1100 NEXT C
 1110 LET R(P)=Q
 1112 LET M(P)=X2*10+Y2+V/10+U/100
 1120 LET Q=0
 1130 RETURN
 1140 IF P=0 THEN 1880
 1150 LET J1=-10
 1155 LET J2=1
 1160 FOR F=1 TO P
 1170   IF R(F)<=J1 THEN 1180
 1172   LET J1=R(F)
 1174   LET J2=F
 1180 NEXT F
 1200 LET X2=INT(M(J2)/10)
 1210 LET Y2=INT(M(J2)-X2*10)
 1220 LET V=INT((M(J2)-INT(M(J2)))*10)
 1230 LET U=INT((M(J2)-X2*10-Y2-V/10)*100+.5)
 1235 PRINT "I MOVE FROM ";X2;Y2,"TO ";U;V
 1240 LET F=0
 1245 LET P2=P
 1250 LET P=0
 1260 LET K=0
 1270 IF V<>1 THEN 1300
 1280 LET S(U,V)=2*G
 1290 GOTO 1310
 1300 LET S(U,V)=S(X2,Y2)
 1310 LET S(X2,Y2)=0
 1320 IF ABS(X2-U)<>2 THEN 1340
 1330 LET S((X2+U)/2,(Y2+V)/2)=0
 1340 GOTO 1370
 1345 PRINT "BOARD";
 1350 INPUT D
 1360 IF D=0 THEN 1390
 1370 GOSUB 1410
 1375 IF F9=0 THEN  PRINT "GEE - I WIN, THANKS FOR THE GAME": STOP
 1390 GOSUB 1580
 1400 RETURN
 1410 PRINT
 1415 LET F9=0: REM...COUNT PLAYER'S PIECES
 1420 FOR Y=8 TO 1 STEP -1
 1425   PRINT " ";Y;
 1430   FOR X=1 TO 8
 1435     LET X9=S(X,Y)
 1438     IF FND(X)=FND(Y) THEN 1450
 1442     PRINT "  ";
 1448     GOTO 1550
 1450     IF S(X,Y)<>0 THEN 1470
 1460     PRINT ". ";
 1465     GOTO 1550
 1470     IF ABS(X9)=2 THEN 1510
 1475     IF X9=-1 THEN 1500
 1480     PRINT "O ";
 1485     LET F9=1
 1490     GOTO 1550
 1500     PRINT "X ";
 1505     GOTO 1550
 1510     IF S(X,Y)<>-2 THEN 1530
 1520     PRINT "X*";
 1525     GOTO 1550
 1530     REM
 1540     PRINT "O*";
 1545     LET F9=1
 1550   NEXT X
 1560   PRINT
 1570 NEXT Y
 1573 PRINT "   1.2.3.4.5.6.7.8."
 1575 RETURN
 1580 PRINT
 1590 PRINT "FROM";
 1600 INPUT E,H
 1610 LET X=E
 1620 LET Y=H
 1630 IF S(X,Y)>0 THEN 1670
 1640 PRINT "THERE IS NO ONE OCCUPING THAT SPACE"
 1650 PRINT
 1660 GOTO 1590
 1670 PRINT ,"TO  ";
 1680 INPUT A,B
 1690 LET X=A
 1700 LET Y=B
 1710 IF S(X,Y)=0 THEN 1742
 1720 PRINT "THAT SPACE IS ALREADY OCCUPIED"
 1730 PRINT
 1740 GOTO 1590
 1742 IF ABS(E-A)=ABS(H-B) THEN 1746
 1744 PRINT "ILLEGAL MOVE": GOTO 1590
 1746 IF ABS(E-A)>2 OR (ABS(E-A)=2 AND S((E+A)/2,(H+B)/2)=0) THEN 1744
 1750 LET S(A,B)=S(E,H)
 1770 LET S(E,H)=0
 1780 LET T=(4.5-(3.5*G))
 1790 IF ABS(E-A)<>2 THEN 1810
 1800 LET S((E+A)/2,(H+B)/2)=0
 1810 IF B<>T THEN 1830
 1820 LET S(A,B)=-2*G
 1830 REM
 1850 RETURN
 1880 PRINT "    VERY GOOD, YOU WIN!"
 1890 PRINT
 1900 PRINT
 1920 END
 2000 FOR F=1 TO P2
 2010   PRINT R(F);M(F),
 2015 NEXT F
 2020 STOP
 3000 GOSUB 1410
 3010 GOTO 1580
 3020 END