BruteForce

public class BruteForce : ISubstringSearch
    {
        public BruteForce()
        {
        }
        public List<int> Search(string fileName, string searchString)
        {
            List<int> result = new List<int>();
            int M = searchString.Length;
            using (StreamReader sr = new StreamReader(fileName))
            {
                string line = sr.ReadLine();
                int N = line.Length;
                for (int i = 0; i < N-M; i++)
                {
                    for (int j = 0; j < M; j++)
                    {
                        if (line[i + j] == searchString[j])
                        {
                            if(j == M - 1)
                            {
                                result.Add(i);
                            }
                        }
                        else { break; }
                    }
                }
            }
            return result;
        }
    }