FUNCTION romtodec(roman$)
    LET num = 0
    LET prenum = 0
    FOR i = len(roman$) to 1 step -1
        LET x$ = (roman$)[i:i+1-1]
        LET n = 0
        IF x$ = "M" then LET n = 1000
        IF x$ = "D" then LET n = 500
        IF x$ = "C" then LET n = 100
        IF x$ = "L" then LET n = 50
        IF x$ = "X" then LET n = 10
        IF x$ = "V" then LET n = 5
        IF x$ = "I" then LET n = 1
        IF n < prenum then LET num = num-n else LET num = num+n
        LET prenum = n
    NEXT i

    LET romtodec = num
END FUNCTION

!Testing
PRINT "MCMXCIX = "; romToDec("MCMXCIX")     !1999
PRINT "MDCLXVI = "; romToDec("MDCLXVI")     !1666
PRINT "XXV     = "; romToDec("XXV")         !25
PRINT "CMLIV   = "; romToDec("CMLIV")       !954
PRINT "MMXI    = "; romToDec("MMXI")        !2011
END