Stack in c#

 public static void SaveStack() {

            string result = "Hello World";
            Stack st = new Stack();
            for (int i = 0; i < result.Length; i++)
            {
                st.Push(result[i]);
            }

            var zzz=st.Peek();
            Console.WriteLine("zzz:" + zzz);
            //st.Clear();
            var r = st.ToArray();
            Console.WriteLine(string.Join(",",r));
            Console.ReadLine();
}