10 DEFINT A-Z
20 FOR I=0 TO 31
30 N=I:GOSUB 200:E=R:REM Encode
40 N=E:GOSUB 300:D=R:REM Decode
50 N=I:GOSUB 400:I$=R$:REM Binary format of input
60 N=E:GOSUB 400:E$=R$:REM Binary format of encoded value
70 N=D:GOSUB 400:D$=R$:REM Binary format of decoded value
80 PRINT USING "##: \   \ => \   \ => \   \ => ##";I;I$;E$;D$;D
90 NEXT
100 END
200 REM Gray encode
210 R = N XOR N\2
220 RETURN
300 REM Gray decode
310 R = N
320 N = N\2
330 IF N=0 THEN RETURN
340 R = R XOR N
350 GOTO 320
400 REM Binary format
410 R$ = ""
420 R$ = CHR$(48+(N AND 1))+R$
430 N = N\2
440 IF N=0 THEN RETURN ELSE 420