You can choose the number of guesses you're allowed, making it more difficult for yourself as you get more practiced.
1 REM**BULLS AND COWS** **BBC VERSION** by I.THOMAS from Spectrum program by R.Erskin e 10 VDU23,255,0,96,254,62,62,34,34,34 20 GOSUB580 30 DIMA(4),H(4) 40 CLS 50 R=RND(1):INPUTTAB(0,19)"How many guesse s do you want (1-20) ?"T 60 IFT<1 OR T>20 GOTO50 70 GOSUB320 80 CLS:PRINTTAB(0,19)CHR$&86"I have chosen my number":TIME=0:REPEAT:UNTILTIME>100 90 GOSUB370 100 FORQ=1TOT 110 PRINTTAB(0,25)"Enter guess ";Q;:INPUT G 120 PRINTTAB(13,25)" " 130 IFG<1000 OR G>9999 GOTO110 140 GOSUB190:GOSUB450 150 IFBL<4 NEXTQ 160 TIME=0:REPEAT:UNTILTIME>100:GOSUB530 170 COLOUR10:PRINT'" Press Space for a nother go" 180 GOSUB650:MODE7:CLEAR:GOTO30 190 BL=0:WH=0 200 G$=STR$(G) 210 FORX=1TO4 220 A(X)=VAL(MID$(G$,X,1)):H(X)=0 230 NEXT:FORX=1TO4 240 IFA(X)=N(X) BL=BL+1:H(X)=1 250 NEXT:FORX=1TO4 260 FORY=1TO4 270 IFH(Y)GOTO290 280 IFA(X)=N(Y) WH=WH+1:H(Y)=1:Y=4 290 NEXTY 300 NEXTX 310 RETURN 320 DIMN(4) 330 FORX=1TO4 340 N(X)=RND(9) 350 NEXTX 360 RETURN 370 MODE2 380 GCOL107,0:MOVE0,255:MOVE1279,255 390 PLOT85,0,957:DRAW1279,255 400 PLOT85,1279,957 410 COLOUR2:PRINTTAB(4,30)"ANSWER: ";:COLOU R129:COLOUR9:VDU19,9,1;0;0:FORX=1TO4:PRINT;N( X);:NEXT 420 COLOUR128:COLOUR7 430 VDU5:GCOL0,0:FORX=1TOT:MOVE31,957-X*32: PRINT;X:NEXT:VDU4 440 RETURN 450 VDU5:GCOL0,4:MOVE191,957-Q*32:PRINT;G 460 GCOL0,7:MOVE640,957-Q*32 470 IFWH=0 GOTO490 480 FORX=1TOWH:VDU255,32:NEXT 490 IFBL=0 GOTO520 500 GCOL0,0 510 FORX=1TOBL:VDU255,32:NEXT 520 VDU4:RETURN 530 VDU19,9,7;0;:IFBL<4 GOTO560 540 COLOUR3:PRINTTAB(0,25)"You are correct" 550 RETURN 560 COLOUR1:PRINTTAB(0,25)"You are wrong" 570 RETURN 580 MODE7:PRINT''CHR$141;CHR$&81;CHR$157;CH R$&83" BULLS AND COWS "CHR$ 156'CHR$141;CHR$&81;CHR$157;CHR$&83" BULLS AND COWS "CHR$156 590 PRINT''''CHR$&85" In Bulls and Cow s the computer"'CHR$&85" chooses a four dig it number which" 600 PRINTCHR$&85" you have to guess."''CH R$&85" Each time you enter a four digit"'C HR$&85" guess,the computer will give you" 610 PRINTCHR$&85" clues: each Bull indicate s a correct"'CHR$&85" digit in the correct position and" 620 PRINTCHR$&85" each Cow indicates a cor rect digit"'CHR$&85" in the wrong position." 630 PRINTCHR$&85" Bulls are black, Cows are white" 640 PRINTTAB(0,21)CHR$136;CHR$&83" P ress Space to start" 650 REPEATUNTILGET=32:RETURN