PROGRAM ROMAN2ARAB

DIM R%[7]

PROCEDURE TOARAB(ROMAN$->ANS%)
      LOCAL I%,J%,P%,N%
      FOR I%=LEN(ROMAN$) TO 1 STEP -1 DO
        J%=INSTR("IVXLCDM",MID$(ROMAN$,I%,1))
        IF J%=0 THEN
            ANS%=-9999  ! illegal character
            EXIT PROCEDURE
        END IF
        IF J%>=P% THEN
            N%+=R%[J%]
          ELSE
            N%-=R%[J%]
        END IF
        P%=J%
      END FOR
      ANS%=N%
END PROCEDURE

BEGIN
  R%[]=(0,1,5,10,50,100,500,1000)
  TOARAB("MCMXCIX"->ANS%)         PRINT(ANS%)
  TOARAB("MMXII"->ANS%)           PRINT(ANS%)
  TOARAB("MDCLXVI"->ANS%)         PRINT(ANS%)
  TOARAB("MMMDCCCLXXXVIII"->ANS%) PRINT(ANS%)
END PROGRAM