Console.Write("enter a word to encrypt: ");
            string s = Console.ReadLine();
            Console.Write("Enter key: ");
            int key = int.Parse(Console.ReadLine());
            for (int i = 0; i < s.Length; Console.Write((char)(((int)s[i] - 96 + key) % 26 + 96)), ++i) ;

            Console.ReadKey();