Count number of similar values in an array

Please try the FindAll method of List class:

            List il = new List();
            il.Add(100);
            il.Add(50);
            il.Add(20);
            il.Add(120);

            List sub = il.FindAll(delegate(int p) { return p >= 100; });

            foreach (int i in sub)
                Console.WriteLine(i);