Roman numerals to integers

Question

I have a transfer with products that unfortunately has to get matched by product name. The biggest issue here is I might get duplicate products on account of roman numbers.

Answer 1

This is my solution

public int SimplerConverter(string number)
    {
        number = number.ToUpper();
        var result = 0;

        foreach (var letter in number)
        {
            result += ConvertLetterToNumber(letter);
        }

        if (number.Contains("IV")|| number.Contains("IX"))
            result -= 2;

        if (number.Contains("XL")|| number.Contains("XC"))
            result -= 20;

        if (number.Contains("CD")|| number.Contains("CM"))
            result -= 200;


        return result;



    }

    private int ConvertLetterToNumber(char letter)
    {
        switch (letter)
        {
            case 'M':
            {
                return 1000;
            }

            case 'D':
            {
                return 500;
            }

            case 'C':
            {
                return 100;
            }

            case 'L':
            {
                return 50;
            }

            case 'X':
            {
                return 10;
            }

            case 'V':
            {
                return 5;
            }

            case 'I':
            {
                return 1;
            }

            default:
            {
                throw new ArgumentException("Ivalid charakter");
            }



        }

    }