public static void Main()
Console.Write("Deret Kuadrat:");
Console.WriteLine(".............=?");
Console.WriteLine("Hitung Lagi? [Y/T]");
if (d == "Y" || d == "y" ){
else if ( d == "T" || d == "t" ){
Console.WriteLine("Terima Kasih");
else {Console.WriteLine("Mohon Ikut Intruksi, Buka ulang Aplikasi");break;}