ROT 13 algorithm

Is this it? using System; namespace csConsole { class Rot13 { public static string Encode(String s) { char[] chars = new char[s.Length]; for (int i = 0; i < s.Length; i++) { int c = s[i]; if (c >= 'A' && c <= 'M') chars[i] = ((char) (c+13)); else if (c >= 'N' && c <= 'Z') chars[i] = ((char) (c-13)); else if (c >= 'a' && c <= 'm') chars[i] = ((char) (c+13)); else if (c >= 'n' && c <= 'z') chars[i] = ((char) (c-13)); else chars[i] = ((char) c); } return new string(chars); } public static string Decode(String s) { char[] chars = new char[s.Length]; for (int i = 0; i < s.Length; i++) { int c = s[i]; if (c <= 'A' && c >= 'M') chars[i] = ((char) (c-13)); else if (c <= 'N' && c >= 'Z') chars[i] = ((char) (c+13)); else if (c <= 'a' && c >= 'm') chars[i] = ((char) (c-13)); else if (c <= 'n' && c >= 'z') chars[i] = ((char) (c+13)); else chars[i] = ((char) c); } return new string(chars); } static void Main(string[] args) { Console.WriteLine("Please enter a string to encode/decode \n\n"); string str = Console.ReadLine(); Console.WriteLine( string.Format("\nOrginal string is {0}" ,str) ); Console.WriteLine( string.Format("Encoded string is {0}" ,Rot13.Encode(str)) ); Console.WriteLine( string.Format("Decoded string is {0}" ,Rot13.Decode(str)) ); Console.Read(); } } }