1.    2.  public interface IPerson    {        void pr();    }    public  class Parent:IPerson    {                public void Initialize()        {            Console.WriteLine("init");        }        public void pr()        {            Console.WriteLine("parent");        }        public string name { get; set; }        public int age { get; set; }    }    public class Child:IPerson    {        public void Initialize()        {            Console.WriteLine("init");        }        public void pr()        {            Console.WriteLine("child");        }        public  string name { get; set; }       public int age { get; set; }    }