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

namespace ConsoleApplication1
{
    class father
    {
        private int a;
        public void showstring()
        {
            Console.Write("父類中的方法");
        }
        public int Ap
        {
            get {return a;}
            set { a = value; }
    }
    }
    class son : father
    {
        public void sonshowstring()
        {
            Console.Write("子類中的方法");
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            father fa = new father();
            fa.showstring();
            son so = new son();
           father fa1 = so;
           fa1.showstring();
        }
    }
}


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

namespace ConsoleApplication1
{
    class father
    {
        private int a;
        public void showstring()
        {
            Console.Write("父類中的方法");
        }
        public int Ap
        {
            get {return a;}
            set { a = value; }
    }
    }
    class son : father
    {
        public void sonshowstring()
        {
            Console.Write("子類中的方法");
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            father fa = new father();
            fa.showstring();
           father fa1=new son();
         fa1.showstring()
        }
    }
}

请问这两个加粗部份实例化对象时，效果有区别嘛？？是否所达到的目的是一样呢？

一个叫拷贝赋值
一个叫类型转换

那在調用時，有沒有什麼要求呢？