static void Main(string[] args) { Student student1 = new Student(1, "M.Cong", "Ha noi", 30); Student student2 = new Student(); student2.SetID(2); student2.SetName("Ph. Quang Khanh"); student2.SetAddress("Lang Son"); student2.SetAge(25); Console.WriteLine(student1.ToString()); Console.WriteLine(student2.ToString()); }