String similarity algorithms?

Question

I need to compare 2 strings and calculate their similarity, to filter down a list of the most similar strings.

Eg. searching for \"dog\" would return

1. d

Answer 1

class Program { 
    static int ComputeLevenshteinDistance(string source, string target) {
        if ((source == null) || (target == null)) return 0;
        if ((source.Length == 0) || (target.Length == 0)) return 0;
        if (source == target) return source.Length;

        int sourceWordCount = source.Length;
        int targetWordCount = target.Length;

        int[,] distance = new int[sourceWordCount + 1, targetWordCount + 1];

        // Step 2
        for (int i = 0; i <= sourceWordCount; distance[i, 0] = i++);
        for (int j = 0; j <= targetWordCount; distance[0, j] = j++);

        for (int i = 1; i <= sourceWordCount; i++) {
            for (int j = 1; j <= targetWordCount; j++) {
                // Step 3
                int cost = (target[j - 1] == source[i - 1]) ? 0 : 1;

                // Step 4
                distance[i, j] = Math.Min(Math.Min(distance[i - 1, j] + 1, distance[i, j - 1] + 1), distance[i - 1, j - 1] + cost);
            }
        }

        return distance[sourceWordCount, targetWordCount]; 
    }

    static void Main(string[] args){ 
       Console.WriteLine(ComputeLevenshteinDistance ("Stackoverflow","StuckOverflow"));
       Console.ReadKey();
    }
}