Converting integers to roman numerals

Question

I\'m trying to write a function that converts numbers to roman numerals. This is my code so far; however, it only works with numbers that are less than 400. Is there a quick

Answer 1

One more straight forward solution. Trying to improve slightly the performance I use StringBuilder, iterate through less keys (one the other site of course LINQ-where might add additional delay)

public class ArabicToRomanConverter
{
    private static readonly Dictionary _romanDictionary = new Dictionary
    {
        {1000,"M"},
        {900,"CM"},
        {500,"D"},
        {400,"CD"},
        {100,"C"},
        {90,"XC"},
        {50,"L"},
        {40,"XL"},
        {10,"X"},
        {9,"IX"},
        {5,"V"},
        {4,"IV"},
        {1 ,"I"}
    };

    public ArabicToRomanConverter()
    {

    }

    public string Convert(int arabicNumber)
    {
        StringBuilder romanNumber = new StringBuilder();
        var keys = _romanDictionary.Keys.Where(k => arabicNumber >= k).ToList();
        for (int i = 0; i < keys.Count && arabicNumber > 0; i++)
        {
            int ckey = keys[i];
            int division = arabicNumber / ckey;
            if (division != 0)
            {
                for (int j = 0; j < division; j++)
                {
                    romanNumber.Append(_romanDictionary[ckey]);
                    arabicNumber -= ckey;
                }
            }
        }

        return romanNumber.ToString();
    }
}