Program to convert a Roman Numeral into a Decimal Number

 Date:- 9th December 2022, Python Lab.

The code for getting the number of digits shows the two ways to get the output, the second function uses the len function and shows how easy it is to do things using functions, and the first one shows a traditional way of approaching the same problem.

def convert(str):

    def getNum(st1):

        if (st1 == 'I'):

            return 1

        if (st1 == 'V'):

            return 5

        if (st1 == 'X'):

            return 10

        if (st1 == 'L'):

            return 50

        if (st1 == 'C'):

            return 100

        if (st1=='D'):

            return 500

        if (st1=='M'):

            return 1000

#         if(st1=='-'):

            return None

    curr = 0

    num=0

 

    while (num<len(str)):

        str1=getNum(str[num])

 

        if (num+1<len(str)):

            str2=getNum(str[num + 1])

 

            if (str1 >= str2):

 

                curr = curr + str1

                num = num + 1

            else:

                curr = curr + str2 - str1

                num = num + 2

        else:

            curr = curr + str1

            num = num + 1

 

    return curr

print(convert("MMMM"))

''' To get the number of digits in a decimal number without using any function

    like len() '''

def count(num):

    coun=0

    while(num!=0):

        coun+=1

        num=num//10

    return coun

def count1(num):

    return len(str(num))

print(count(56732))

print(count1(56732))