C# 抽象类

abstract class bProgram
    {
        public void a()
        {
            Console.WriteLine("I am bProgram ,I am a().");
        }
    }

    abstract class aProgram:bProgram
    {
        public abstract void f();
    }
    class Program:aProgram
    {
        public override void f()
        {
            Console.WriteLine("I am bProgram,I am f().");
        }

        static void Main(string[] args)
        {
            Program p =new Program();
            p.f();
            Console.WriteLine("I am Program");
            Console.Read();
        }
    }