string str = "Insus.NET";

 public void SplitString(string str)
        {
            int len = str.Length;
            for (int i = 0; i < len; i++)
            {
                Console.WriteLine(str[i]);
            }
        }

 public void SplitString0(string str)
        {
            string[] arr = new string[str.Length];
            for (int i = 0; i < str.Length; i++)
            {
                arr[i] = str[i].ToString();
            }

            foreach (string s in arr)
            {
                Console.WriteLine(s);
            }
        }

 public void SplitString1(string str)
        {
            foreach (Char c in str.ToCharArray())
            {
                Console.WriteLine(c);
            }
        }

public void SplitString2(string str)
        {
            string[] arr = str.Select(s => s.ToString()).ToArray();

            foreach (string s in arr)
            {
                Console.WriteLine(s);
            }
        }