public static void Main(string[] args)
string str = Console.ReadLine();
char[] a = str.ToCharArray();
Console.WriteLine("Entered String name is {0}", str);
for (int i = 0; i < str.Length; i++)
if (a[i] >= 65 && a[i] <= 90)
else if (a[i] >= 97 && a[i] <= 122)
Console.WriteLine("Invalid");
Console.WriteLine("Entered text " + str[i] + " encoded string to next alphabet is " + a[i]);