June 26. NET face question (program part) as long as do understand these 3 questions must be able to leave the rookie title!

Description: 1, if you just want to know the correct answer, copy the code to run on vs.

2, these 3 questions I will not do, seek guidance (only need to tell me the knowledge point of the investigation on the line ~)

1. What is wrong with the code below, and if so, how to correct it? (I feel right ~ ~)

    public class A    {public        virtual void F ()        {            Console.WriteLine ("A.F");        }    }    Public abstract class B:a    {public        abstract override void F ();    }

2, a comprehensive problem, the following program output is? (feeling very comprehensive, ask the master to tell this question have examined what knowledge points ~ ~ ~)

Using System;namespace consoleapplication1{    internal class program    {        private static void Main (string[] args)        {            var a = new A ();            A B = new B ();            A.fun2 (b);            B.fun2 (a);            Console.readkey ();        }    }    Internal Class A    {public        a ()        {            Console.WriteLine ("a");        }        public virtual void Fun1 (int i)        {            Console.WriteLine (i);        }        public virtual void Fun2 (a a)        {            a.fun1 (1);            FUN1 (3);        }    }    Internal class b:a    {public        B ()        {            Console.WriteLine ("B");        }        public override void Fun1 (int i)        {            base. FUN1 (i + 1);        }        Public new void Fun2 (a a)        {            a.fun1 (2);            FUN1 (5);}}    

3, the overall problem, the following program output is? (also answer wrong, ask to tell what knowledge points have been examined ~ ~)

Using System;namespace consoleapplication2{    internal class program    {        private static void Main (string[] args)        {            Console.WriteLine ("X={0},y={1}", A.x.tostring ("X2"), B.y.tostring ("X"));            Console.readkey ();        }    }    public class A    {public        static int x;    }    public class B    {public        static int y = a.x + 1;        Static B ()        {        }}    }

June 26. NET face question (program part) as long as do understand these 3 questions must be able to leave the rookie title!