static void Main(string[] args) { Student st = new Student(); Console.WriteLine((Student)st.DeepCopy() + "\n" + st); Console.WriteLine("Enter file name."); string Filename = "D:/hello.dat"; //Console.ReadLine(); if (File.Exists(Filename)) { st.Load(Filename); } else { Console.WriteLine("File not exist!"); st.Save(Filename); } Console.WriteLine(st); st.AddFromConsole(); st.Save(Filename); Console.WriteLine(st); st.AddFromConsole(); Student.Save(Filename, st); Console.WriteLine(st); }