0010 PROC compare(guess$,secret$)
0020   correct:=0
0021   misplaced:=0
0030   FOR i:=1 TO 4 DO
0040     IF guess$(i:i)=secret$(i:i) THEN
0050       correct:=correct+1
0051       guess$(i:i):=" "
0052       secret$(i:i):=" "
0060     ENDIF
0070   ENDFOR i
0071   FOR i:=1 TO 4 DO
0072     FOR c:=1 TO 4 DO
0073       IF guess$(i:i)<>" " AND guess$(i:i)=secret$(c:c) THEN
0074         misplaced:=misplaced+1
0075         guess$(i:i):=" "
0076         secret$(c:c):=" "
0077       ENDIF
0078     ENDFOR c
0079   ENDFOR i
0080   PRINT AT CURROW-1,24: "Correct: ",correct," Misplaced: ",misplaced
0090 ENDPROC compare
0100 FUNC isin(v,s$)
0110   FOR i:=1 TO LEN(s$) DO
0120     IF VAL(s$(i:i))=v THEN RETURN TRUE
0130   ENDFOR i
0140   RETURN FALSE
0150 ENDFUNC isin
0160 FUNC validate(guess$)
0170   IF LEN(guess$)<>4 THEN
0180     RETURN FALSE
0190   ENDIF
0200   FOR i:=1 TO 4 DO
0210     IF NOT guess$(i:i) IN "0123456789" THEN RETURN FALSE
0220   ENDFOR i
0230   RETURN TRUE
0240 ENDFUNC validate
0250 secret$:=""
0260 FOR i:=1 TO 4 DO
0270   REPEAT
0280     candidate:=INT(RND*8)+1
0290   UNTIL NOT isin(candidate,secret$)
0300   secret$:=secret$+STR$(candidate)
0310   PRINT "Generated value numer ",i," which was ",candidate
0320 ENDFOR i
0330 PAGE
0340 PRINT "Welcome to Mastermind by RetroComputing with Mike"
0350 guesses:=0
0360 REPEAT
0370   INPUT "Guess the code:": guess$
0380   IF NOT validate(guess$) THEN
0390     PRINT "Your guess should consists of 4 numbers"
0400   ELSE
0410     guesses:=guesses+1
0420     compare(guess$,secret$)
0430   ENDIF
0440 UNTIL guess$=secret$
0450 PRINT "Congratulations, you guessed the secret in ",guesses," attempts"