static void Main(string[] args) { string contactType; string name; int age; string address; int contact_number; while (true) { Console.WriteLine("Enter contactType [P]rofessor/[S]tudent):"); contactType = Console.ReadLine(); ; if ((contactType != "P") && (contactType != "S")) { Console.WriteLine("Valid values :[P]rofessor/[S]tudent"); Console.ReadLine(); break; } else { Console.WriteLine("Enter contact details below:"); Console.WriteLine("Enter name"); name = Console.ReadLine(); Console.WriteLine("Enter age"); age = Convert.ToInt32(Console.ReadLine()); Console.WriteLine("Enter Address"); address = Console.ReadLine(); Console.WriteLine("Enter contact number "); contact_number = Convert.ToInt32(Console.ReadLine()); switch (contactType) { case "P": Console.WriteLine("Professor created"); Professor p1 = new Professor(name, age, address, contact_number); p1.displayProfessor(); Console.ReadLine(); break; case "S": Console.WriteLine("Student created"); Student s1 = new Student(name, age, address, contact_number); s1.displayStudent(); Console.ReadLine(); break; default: Console.WriteLine("Invalid value"); break; } break; } } }