C# abstract和virtual

    public abstract class demoFatnerClass
    {
        public void func()      //普通方法 
        {
            Console.WriteLine("father‘s ordinary fun.");
        }
        public virtual void virFunc()    //虚函数 选择性被子类重写
        {
            Console.WriteLine("father ‘s virtual fun.");
        }
        public abstract void absFunc();    //抽象方法 子类必须重写该方法不写编译器会报错
    }
 
    public class demoSonClass:demoFatnerClass
    {
        public override void absFunc()    //重写抽象方法
        {
            Console.WriteLine("son overriden abstract function.");
        }
        public override void virFunc()     //重写父类虚函数，可以不写
        {
            Console.WriteLine("son overriden virtual function.");
        }
    }
 
class Program
    {
        static void Main()
        {
            demoSonClass son = new demoSonClass();
            son.func();
            son.absFunc();
            son.virFunc();
            Console.ReadKey();
        }
    }