using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication19
{
    class kaka
    {
        private int x;
        private int y;
        public int X
        {
            get { return x;}
            set { x = value; }
        }
        public int Y
        {
            get { return y;}
            set { y = value; }
        }
        public virtual int add1()
        {
            return X + Y;
        }
    }
    class caca : kaka
    {
        public voerride int add1()
        {
            
            return X+Y+X;
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            caca aa=new caca();
            kaka bb = (kaka)aa;
            aa.X = 3;
            aa.Y = 3;
            Console.WriteLine(bb.add1());
            Console.WriteLine(aa.add1());
            Console.ReadLine();

        }
    }
}
这个运行结果是9,9  而如果我把override替换为new则是6,9.
为什么呢？书上说这样效果是一样的呀？