INSTALL @lib$+"STRINGLIB"

      PRINT "   Decimal    Binary      Gray   Decoded"
      FOR number% = 0 TO 31
        gray% = FNgrayencode(number%)
        PRINT number% "     " FN_tobase(number%, 2, 5) ;
        PRINT "     " FN_tobase(gray%, 2, 5) FNgraydecode(gray%)
      NEXT
      END

      DEF FNgrayencode(B%) = B% EOR (B% >>> 1)

      DEF FNgraydecode(G%) : LOCAL B%
      REPEAT B% EOR= G% : G% = G% >>> 1 : UNTIL G% = 0
      = B%