Solutions

The following sections describe solutions to the preceding problems. You can download the example solutions, to see additional details and to experiment with the programs at https://github.com/PacktPublishing/The-Modern-CSharp-Challenge/tree/master/Chapter05.

56. Roman numerals

There are many ways that you could approach this problem. I decided to use lookup tables to make things faster and simpler.

The following code shows a string extension method that converts a Roman numeral string into a long integer:

// Maps letters to numbers.
private static Dictionary<char, long> LetterValues = null;

// Convert Roman numerals into an integer.
public static long ToArabic(this string roman)
{
    // Initialize the letter lookup table if
    // it hasn't been initialized yet.
    if (LetterValues == null)
    {
        LetterValues = new Dictionary<char, long>();
        LetterValues.Add('I', 1);
        LetterValues.Add('V', 5);
        LetterValues.Add('X', 10);
        LetterValues...