'=========================================================================== ' Subject: Connect 4 in a row Date: 07-14-01 ( : ) ' Author: Richard Kelly Code: PB, QB, firstbasic ' Origin: newson@37.com Packet: GAMES.ABC '=========================================================================== 1 'Name: Connect Four in a Row 2 'Author: Richard Kelly (Newson@37.com) 3 'Category: Games or Demos 4 'Date released: 07/14/01 5 ' 6 'This is a text-based version of the old "Connect 4" game. The computer is 7 'programmed to play against you, but the algorithm has many problems with 8 'it: The computer doesn't "look ahead" far enough, sometimes it doesn't 9 'notice areas that are one move away from a diagonal win, and so on. 10 'I've re-done the algorithm from scratch twice already and it *still* 11 'doesn't work right, and it has a long way to go before it ever will. I've 12 'gotten burned out on this project and I'm releasing it to the Public 13 'Domain for anyone else out there who wants to mess around with it. Just 14 'so you know: Z$ has each column labeled with a "priority number", so a 15 'column with a "1" will be played before a column with "2", ect.. Also, 16 'I expect that the algorithm will have to be re-written *again* in order to 17 'work right. Sorry about that, and my apologies also for the lack of 18 'documentation. 19 ' 20 'This runs on GW-BASIC, QB v1.1-v7.0, PowerBASIC, and FirstBASIC. 100 DIM A$(6), B$(0), M$(0): GOTO 660 109 'Has someone won? 110 WR = 0: WI = 0: O0 = 0: O1 = 0: O2 = 0: O3 = 0: FOR Y = 1 TO 3: FOR X = 1 TO 4: A$ = A$(Y): B$ = A$(Y + 1): C$ = A$(Y + 2): D$ = A$(Y + 3): WI = 1: IF MID$(A$, X, 4) = "1111" AND WR = 0 THEN WR = 1: GOSUB 1970 120 IF MID$(A$, X, 4) = "2222" AND WR = 0 THEN WR = 2: GOSUB 1970 130 WI = 2: IF MID$(A$, X, 1) + MID$(B$, X, 1) + MID$(C$, X, 1) + MID$(D$, X, 1) = "1111" AND WR = 0 THEN WR = 1: GOSUB 1970 140 IF MID$(A$, X, 1) + MID$(B$, X, 1) + MID$(C$, X, 1) + MID$(D$, X, 1) = "2222" AND WR = 0 THEN WR = 2: GOSUB 1970 150 WI = 3: IF MID$(D$, X, 1) + MID$(C$, X + 1, 1) + MID$(B$, X + 2, 1) + MID$(A$, X + 3, 1) = "1111" AND WR = 0 THEN WR = 1: GOSUB 1970 160 IF MID$(D$, X, 1) + MID$(C$, X + 1, 1) + MID$(B$, X + 2, 1) + MID$(A$, X + 3, 1) = "2222" AND WR = 0 THEN WR = 2: GOSUB 1970 170 WI = 4: IF MID$(A$, X, 1) + MID$(B$, X + 1, 1) + MID$(C$, X + 2, 1) + MID$(D$, X + 3, 1) = "1111" AND WR = 0 THEN WR = 1: GOSUB 1970 180 IF MID$(A$, X, 1) + MID$(B$, X + 1, 1) + MID$(C$, X + 2, 1) + MID$(D$, X + 3, 1) = "2222" AND WR = 0 THEN WR = 2: GOSUB 1970 190 NEXT X, Y: WI = 1: FOR Y = 4 TO 6: FOR X = 1 TO 4: IF MID$(A$(Y), X, 4) = "1111" AND WR = 0 THEN WR = 1: GOSUB 1970 200 IF MID$(A$(Y), X, 4) = "2222" AND WR = 0 THEN WR = 2: GOSUB 1970 210 NEXT X, Y: WI = 2 220 FOR Y = 1 TO 3: FOR X = 4 TO 7: R$ = MID$(A$(Y), X, 1) + MID$(A$(Y + 1), X, 1) + MID$(A$(Y + 2), X, 1) + MID$(A$(Y + 3), X, 1): IF R$ = "1111" AND WR = 0 THEN WR = 1: GOSUB 1970 230 IF R$ = "2222" AND WR = 0 THEN WR = 2: GOSUB 1970 240 NEXT X, Y: X = 0: Y = 0: WR = 0: WI = 0: RETURN 249 'The computer's turn. 250 COLOR 7, 0: LOCATE 20, 1: PRINT "This is the computer's move. " 260 A = 0: IF MID$(A$(6), 4, 1) = " " THEN A = 4: GOTO 610 270 Z$ = " ": FOR X = 1 TO 7: IF MID$(A$(1), X, 1) > " " THEN Y$ = "0": GOSUB 630: GOTO 520 278 'The computer looks for a winning move or a place where the player is 279 ' about win (marked as "1" for Y$). 280 OT = 0: FOR Y = 6 TO 1 STEP -1: IF MID$(A$(Y), X, 1) = " " AND OT = 0 THEN OT = Y 290 NEXT Y: Y = OT: Y$ = " ": A = X: IF Y > 3 THEN 320 300 A$ = MID$(A$(Y + 1), X, 1) + MID$(A$(Y + 2), X, 1) + MID$(A$(Y + 3), X, 1): IF A$ = "222" THEN 610 310 IF A$ = "111" THEN Y$ = "1": GOSUB 630 320 IF X > 4 THEN 350 330 A$ = MID$(A$(Y), X + 1, 3): IF A$ = "222" THEN 610 340 IF A$ = "111" THEN Y$ = "1": GOSUB 630 350 IF X < 4 THEN 380 360 A$ = MID$(A$(Y), X - 3, 3): IF A$ = "222" THEN 610 370 IF A$ = "111" THEN Y$ = "1": GOSUB 630 380 IF X = 1 OR X > 5 THEN 410 390 A$ = MID$(A$(Y), X - 1, 4): IF A$ = "2 22" THEN 610 400 IF A$ = "1 11" THEN Y$ = "1": GOSUB 630 410 IF X < 3 OR X = 7 THEN 440 420 A$ = MID$(A$(Y), X - 2, 4): IF A$ = "22 2" THEN 610 430 IF A$ = "11 1" THEN Y$ = "1": GOSUB 630 440 IF X < 4 THEN 510 450 IF Y < 4 THEN 490 460 A$ = MID$(A$(Y - 3), X - 3, 1) + MID$(A$(Y - 2), X - 2, 1) + MID$(A$(Y - 1), X - 1, 1): IF A$ = "222" THEN 610 470 IF A$ = "111" THEN Y$ = "1": GOSUB 630 480 IF Y > 3 THEN 510 490 A$ = MID$(A$(Y + 3), X - 3, 1) + MID$(A$(Y + 2), X - 2, 1) + MID$(A$(Y + 1), X - 1, 1): IF A$ = "222" THEN 610 500 IF A$ = "111" THEN Y$ = "1": GOSUB 630 509 'The routine continues on Line 1180. 510 GOTO 1180 519 'Sum up the computer player's decisions. Now what are his options? 520 NEXT X: GOSUB 1980: A = INSTR(Z$, "1"): IF A > 0 THEN 610 ELSE 540 530 A = INT(RND * 7 + 1): IF MID$(Z$, A, 1) <> " " THEN 530 ELSE 610 538 'I'm pretty sure I never programmed in the routine that gave Y$ the values 539 ' "6" and "5", since the new algorithm never worked right. 540 A = INSTR(Z$, "6"): IF A > 0 THEN 610 550 A = INSTR(Z$, "5"): IF A > 0 THEN 610 560 A = INSTR(Z$, "4"): IF A > 0 THEN 610 570 A = INSTR(Z$, " "): IF A > 0 THEN 530 580 A = INSTR(Z$, "2"): IF A > 0 THEN 610 590 A = INSTR(Z$, "3"): IF A > 0 THEN 610 600 A = INT(RND * 7 + 1): IF MID$(A$(1), A, 1) <> " " THEN 600 610 'LOCATE 20,1:PRINT STRING$(38,32); 620 RETURN 630 Z$ = LEFT$(Z$, X - 1) + Y$ + RIGHT$(Z$, 7 - X): RETURN 640 LOCATE 18, LO + 1: PRINT " ": RETURN 650 LOCATE 21, 1: PRINT STRING$(150, 32); : LOCATE 18, LO + 1: PRINT "1 2 3 4 5 6 7": RETURN 659 'This seems to be where the title screen is. 660 SCREEN 0, 0: WIDTH 40: COLOR 7, 0: LOCATE 1, 1, 0: CLS : M0$ = CHR$(218): FOR T = 1 TO 6: M0$ = M0$ + CHR$(196) + CHR$(194): NEXT: M0$ = M0$ + CHR$(196) + CHR$(191) 670 RANDOMIZE TIMER: M2$ = "": FOR T = 1 TO 7: M1$ = M1$ + CHR$(179) + CHR$(219): NEXT: M1$ = M1$ + CHR$(179): PLAY "MLT150L24" 680 M2$ = CHR$(195): FOR T = 1 TO 6: M2$ = M2$ + CHR$(196) + CHR$(197): NEXT: M2$ = M2$ + CHR$(196) + CHR$(180) 690 M3$ = CHR$(192): FOR T = 1 TO 6: M3$ = M3$ + CHR$(196) + CHR$(193): NEXT: M3$ = M3$ + CHR$(196) + CHR$(217) 700 LI = 12: GOSUB 1960: LO = 13: LOCATE 5, 1: PRINT "1 or 2 players?" 710 A$ = INKEY$: IF A$ = "1" THEN P3 = 1: GOTO 740 720 IF A$ = "2" THEN P3 = 2: GOTO 740 730 GOTO 710 740 LOCATE 5, 1: PRINT "Player 1, do you want to go first?" 750 A$ = INKEY$: IF A$ = "Y" OR A$ = "y" THEN PO = 0: GOTO 780 760 IF A$ = "N" OR A$ = "n" THEN PO = 1: GOTO 780 770 GOTO 750 780 LOCATE 5, 1: PRINT STRING$(40, 32); 790 P1 = 0: P2 = 0 800 GOSUB 1940: PR = PO: COLOR 0, 14: LOCATE 5, LO: PRINT M0$; : FOR T = 2 TO 10 STEP 2: LOCATE T + 4, LO: PRINT M1$; : LOCATE T + 5, LO: PRINT M2$; : NEXT: LOCATE 16, LO: PRINT M1$; : LOCATE 17, LO: PRINT M3$; : FOR T = 1 TO 6: A$(T) = STRING$(7, 32): NEXT: COLOR 7, 0 810 LOCATE 19, 1: PRINT "Player 1 ": LOCATE 20, 1: PRINT "Score:"; P1: LOCATE 19, 20: PRINT "Player 2 ": LOCATE 20, 20: PRINT "Score:"; P2 820 LOCATE 22, 1: PRINT "Press [SPACE] to play, [RETURN] to reset score, [HOME] to reset options, and [ESC] to quit."; 830 A$ = INKEY$: IF A$ = CHR$(0) + "G" THEN RUN 840 IF A$ = CHR$(13) THEN P1 = 0: P2 = 0: GOTO 810 850 IF A$ = CHR$(27) THEN 1950 860 IF A$ = " " THEN GOSUB 650: GOTO 880 870 GOTO 830 880 PR = PR + 1: IF PR > 2 THEN PR = 1 890 GOSUB 1140: LOCATE 18, LO + 1: IF PR = 2 AND P3 = 1 THEN GOSUB 250: GOTO 930 900 LOCATE 20, 1: PRINT "Press a number to make your move." 910 GOSUB 1940: GOTO 1900 920 A = VAL(A$): IF MID$(A$(1), A, 1) <> " " THEN 1900 930 X = A: Y = 0: GOSUB 1160: A1 = AX: A2 = AY: IF PR = 1 THEN COLOR 4, 0 ELSE COLOR 1, 0 940 GOTO 960 949 'Drop the "checker". 950 LOCATE A2, A1: PRINT CHR$(220); : PLAY "N0": LOCATE A2, A1: PRINT " "; : PLAY "N0" 960 LOCATE AY, AX: PRINT CHR$(223); : PLAY "N0": LOCATE AY, AX: PRINT CHR$(219); 970 A1 = AX: A2 = AY: IF Y < 6 THEN IF MID$(A$(Y + 1), X, 1) = " " THEN AY = AY + 2: Y = Y + 1: PLAY "N0": GOTO 950 980 COLOR 7, 0: IF PR = 1 THEN MID$(A$(Y), X, 1) = "1" ELSE MID$(A$(Y), X, 1) = "2" 990 GOSUB 110: IF O0 > 0 THEN 1030 1000 IF INSTR(A$(1), " ") > 0 THEN 880 1009 'Tie game! 1010 LOCATE 20, 1: PRINT "The board is full, so the game is a tie.": PRINT : PRINT "Press any key to continue.": WHILE INKEY$ = "": WEND 1020 GOTO 1130 1029 'Someone won. 1030 X = O0: Y = O1: WI = O2: WR = O3: GOSUB 640: IF WR = 1 THEN P1 = P1 + 1: COLOR 16, 4 ELSE P2 = P2 + 1: COLOR 16, 1 1040 GOSUB 1160: ON WI GOTO 1050, 1070, 1110, 1090 1048 'The "blinking row" is drawn in COLOR 16 so it doesn't have to be updated 1049 'continuously. 1050 FOR T = 0 TO 6 STEP 2: LOCATE AY, AX + T: PRINT CHR$(219); : NEXT 1060 GOTO 1120 1070 FOR Y = 0 TO 6 STEP 2: LOCATE AY + Y, AX: PRINT CHR$(219); : NEXT 1080 GOTO 1120 1090 FOR T = 0 TO 6 STEP 2: LOCATE AY + T, AX + T: PRINT CHR$(219); : NEXT 1100 GOTO 1120 1110 FOR T = 0 TO 6 STEP 2: LOCATE AY + 6 - T, AX + T: PRINT CHR$(219); : NEXT 1120 COLOR 7, 0: LOCATE 20, 1: PRINT "Player"; WR; "wins the game. ": LOCATE 22, 1: PRINT "Press any key to continue.": GOSUB 1940: WHILE INKEY$ = "": WEND 1130 LOCATE 20, 1: PRINT STRING$(78, 32); : GOTO 800 1140 COLOR 23, 0: IF PR = 1 THEN LOCATE 19, 10: PRINT CHR$(17); : LOCATE 19, 29: PRINT " "; : COLOR 7, 0: RETURN 1150 LOCATE 19, 10: PRINT " "; : LOCATE 19, 29: PRINT CHR$(17); : COLOR 7, 0: RETURN 1160 AY = (Y * 2) + 4: AX = (X * 2) + LO - 1: RETURN 1170 GOSUB 1960: GOTO 800 1180 IF X > 4 THEN 1250 1190 IF Y < 4 THEN 1230 1200 A$ = MID$(A$(Y - 3), X + 3, 1) + MID$(A$(Y - 2), X + 2, 1) + MID$(A$(Y - 1), X + 1, 1): IF A$ = "222" THEN 610 1210 IF A$ = "111" THEN Y$ = "1": GOSUB 630 1220 IF Y > 3 THEN 1250 1230 A$ = MID$(A$(Y + 3), X + 3, 1) + MID$(A$(Y + 2), X + 2, 1) + MID$(A$(Y + 1), X + 1, 1): IF A$ = "222" THEN 610 1240 IF A$ = "111" THEN Y$ = "1": GOSUB 630 1250 IF X = 1 OR X > 5 THEN 1320 1260 IF Y < 3 OR Y = 6 THEN 1290 1270 A$ = MID$(A$(Y + 1), X - 1, 1) + MID$(A$(Y - 1), X + 1, 1) + MID$(A$(Y - 2), X + 2, 1): IF A$ = "222" THEN 610 1280 IF A$ = "111" THEN Y$ = "1": GOSUB 630 1290 IF Y = 1 OR Y > 4 THEN 1320 1300 A$ = MID$(A$(Y - 1), X - 1, 1) + MID$(A$(Y + 1), X + 1, 1) + MID$(A$(Y + 2), X + 2, 1): IF A$ = "222" THEN 610 1310 IF A$ = "111" THEN Y$ = "1": GOSUB 630 1320 IF X < 3 OR X = 7 THEN 1390 1330 IF Y = 1 OR Y > 4 THEN 1360 1340 A$ = MID$(A$(Y + 2), X - 2, 1) + MID$(A$(Y + 1), X - 1, 1) + MID$(A$(Y - 1), X + 1, 1): IF A$ = "222" THEN 610 1350 IF A$ = "111" THEN Y$ = "1": GOSUB 630 1360 IF Y < 3 OR Y = 6 THEN 1390 1370 A$ = MID$(A$(Y - 2), X - 2, 1) + MID$(A$(Y - 1), X - 1, 1) + MID$(A$(Y + 1), X + 1, 1): IF A$ = "222" THEN 610 1380 IF A$ = "111" THEN Y$ = "1": GOSUB 630 1390 IF X < 3 OR X > 5 THEN 1440 1398 'Check to see if a win is possible by having an "open-ended" three-in-a- 1399 'row. Marked as "4" in Y$. 1400 A$ = MID$(A$(Y), X - 2, 5): IF (A$ = " 2 2 " OR A$ = " 1 1 ") AND Y$ = " " THEN Y$ = "4": GOSUB 630 1410 IF Y < 3 OR Y > 4 THEN 1440 1420 A$ = MID$(A$(Y + 2), X - 2, 1) + MID$(A$(Y + 1), X - 1, 1) + MID$(A$(Y - 1), X + 1, 1) + MID$(A$(Y - 2), X + 2, 1): IF (A$ = " 22 " OR A$ = " 11 ") AND Y$ = " " THEN Y$ = "4": GOSUB 630 1430 A$ = MID$(A$(Y - 2), X - 2, 1) + MID$(A$(Y - 1), X - 1, 1) + MID$(A$(Y + 1), X + 1, 1) + MID$(A$(Y + 2), X + 2, 1): IF (A$ = " 22 " OR A$ = " 11 ") AND Y$ = " " THEN Y$ = "4": GOSUB 630 1440 IF Y = 1 THEN 1870 1450 Y = Y - 1: IF X < 4 THEN 1480 1458 'If a four-in-a-row is two moves away for the computer in this area, mark 1459 'Y$ as "2". For the "enemy", mark it as a "3". 1460 A$ = MID$(A$(Y), X - 3, 3): IF A$ = "222" AND (Y$ = " " OR Y$ = "4") THEN Y$ = "2": GOSUB 630 1470 IF A$ = "111" AND Y$ <> "1" THEN Y$ = "3": GOSUB 630 1480 IF X > 4 THEN 1510 1490 A$ = MID$(A$(Y), X + 1, 3): IF A$ = "222" AND (Y$ = " " OR Y$ = "4") THEN Y$ = "2": GOSUB 630 1500 IF A$ = "111" AND Y$ <> "1" THEN Y$ = "3": GOSUB 630 1510 IF X = 1 OR X > 5 THEN 1540 1520 A$ = MID$(A$(Y), X - 1, 4): IF A$ = "2 22" AND (Y$ = " " OR Y$ = "4") THEN Y$ = "2": GOSUB 630 1530 IF A$ = "1 11" AND Y$ <> "1" THEN Y$ = "3": GOSUB 630 1540 IF X < 3 OR X = 7 THEN 1570 1550 A$ = MID$(A$(Y), X - 2, 4): IF A$ = "22 2" AND (Y$ = " " OR Y$ = "4") THEN Y$ = "2": GOSUB 630 1560 IF A$ = "11 1" AND Y$ <> "1" THEN Y$ = "3": GOSUB 630 1570 IF X < 4 THEN 1640 1580 IF Y < 4 THEN 1610 1590 A$ = MID$(A$(Y - 3), X - 3, 1) + MID$(A$(Y - 2), X - 2, 1) + MID$(A$(Y - 1), X - 1, 1): IF A$ = "222" AND (Y$ = " " OR Y$ = "4") THEN Y$ = "2": GOSUB 630 1600 IF A$ = "111" AND Y$ <> "1" THEN Y$ = "3": GOSUB 630 1610 IF Y > 3 THEN 1640 1620 A$ = MID$(A$(Y + 3), X - 3, 1) + MID$(A$(Y + 2), X - 2, 1) + MID$(A$(Y + 1), X - 1, 1): IF A$ = "222" AND (Y$ = " " OR Y$ = "4") THEN Y$ = "2": GOSUB 630 1630 IF A$ = "111" AND Y$ <> "1" THEN Y$ = "3": GOSUB 630 1640 IF X > 4 THEN 1710 1650 IF Y < 4 THEN 1680 1660 A$ = MID$(A$(Y - 3), X + 3, 1) + MID$(A$(Y - 2), X + 2, 1) + MID$(A$(Y - 1), X + 1, 1): IF A$ = "222" AND (Y$ = " " OR Y$ = "4") THEN Y$ = "2": GOSUB 630 1670 IF A$ = "111" AND Y$ <> "1" THEN Y$ = "3": GOSUB 630 1680 IF Y > 3 THEN 1710 1690 A$ = MID$(A$(Y + 3), X + 3, 1) + MID$(A$(Y + 2), X + 2, 1) + MID$(A$(Y + 1), X + 1, 1): IF A$ = "222" AND (Y$ = " " OR Y$ = "4") THEN Y$ = "2": GOSUB 630 1700 IF A$ = "111" AND Y$ <> "1" THEN Y$ = "3": GOSUB 630 1710 IF X = 1 OR X > 5 THEN 1780 1720 IF Y = 1 OR Y > 4 THEN 1750 1730 A$ = MID$(A$(Y - 1), X - 1, 1) + MID$(A$(Y + 1), X + 1, 1) + MID$(A$(Y + 2), X + 2, 1): IF A$ = "222" AND (Y$ = " " OR Y$ = "4") THEN Y$ = "2": GOSUB 630 1740 IF A$ = "111" AND Y$ <> "1" THEN Y$ = "3": GOSUB 630 1750 IF Y < 3 OR Y = 6 THEN 1780 1760 A$ = MID$(A$(Y + 1), X - 1, 1) + MID$(A$(Y - 1), X + 1, 1) + MID$(A$(Y - 2), X + 2, 1): IF A$ = "222" AND (Y$ = " " OR Y$ = "4") THEN Y$ = "2": GOSUB 630 1770 IF A$ = "111" AND Y$ <> "1" THEN Y$ = "3": GOSUB 630 1780 IF X < 3 OR X = 7 THEN 1850 1790 IF Y < 3 OR Y = 6 THEN 1820 1800 A$ = MID$(A$(Y - 2), X - 2, 1) + MID$(A$(Y - 1), X - 1, 1) + MID$(A$(Y + 1), X + 1, 1): IF A$ = "222" AND (Y$ = " " OR Y$ = "4") THEN Y$ = "2": GOSUB 630 1810 IF A$ = "111" AND Y$ <> "1" THEN Y$ = "3": GOSUB 630 1820 IF Y = 1 OR Y > 4 THEN 1850 1830 A$ = MID$(A$(Y + 2), X - 2, 1) + MID$(A$(Y + 1), X - 1, 1) + MID$(A$(Y - 1), X + 1, 1): IF A$ = "222" AND (Y$ = " " OR Y$ = "4") THEN Y$ = "2": GOSUB 630 1840 IF A$ = "111" AND Y$ <> "1" THEN Y$ = "3": GOSUB 630 1850 Y = Y + 1: IF X > 4 THEN 1870 1860 A$ = MID$(A$(Y), X, 4): IF (A$ = " 22 " OR A$ = " 11 ") AND Y$ = " " THEN Y$ = "4": GOSUB 630 1870 GOTO 1890 1880 A$ = "": IF Y > 0 THEN A$ = A$(Y): RETURN ELSE RETURN 1890 GOTO 520 1900 A$ = INKEY$: IF A$ = CHR$(27) THEN LOCATE 20, 1: PRINT STRING$(38, 32); : GOTO 800 1910 IF A$ = CHR$(16) THEN IF P3 = 1 THEN P3 = 2 ELSE P3 = 1 1920 IF A$ < "1" OR A$ > "7" THEN 1900 1930 GOTO 920 1940 IF INKEY$ <> "" THEN 1940 ELSE RETURN 1950 WIDTH 80: CLEAR : END: RUN 1960 CLS : COLOR 7, 0: LOCATE 1, LI - 4: PRINT "Connect 4 in a Row ver. 0.8": LOCATE 3, LI + 1: PRINT "By Richard Kelly": RETURN 1970 O0 = X: O1 = Y: O2 = WI: O3 = WR: RETURN 1980 FOR X = 1 TO 7: IF MID$(Z$, X, 1) > " " AND MID$(Z$, X, 1) <> "4" AND MID$(Z$, X, 1) <> "2" THEN 2010 1990 OT = 0: FOR Y = 6 TO 1 STEP -1: IF MID$(A$(Y), X, 1) = " " AND OT = 0 THEN OT = Y 2000 NEXT Y: Y = OT: A = X 2010 NEXT X: RETURN