[读书]看看你有没有忽视

今天利用一点休息时间，随便翻了翻桌子上摆的一大摞书，看到了一小段代码，你也试试。

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

using System.IO;

namespace DotNetFramework
{
    class Program
    {
        static void Main(string[] args)
        {
            Point point = new Point();

            point.x = point.y = 1;
            Console.WriteLine(point);

            point.Change(2, 2);
            Console.WriteLine(point);

            object o = point;
            Console.WriteLine(o);

            ((Point)o).Change(3, 3);
            Console.WriteLine(o);

            ((IChangeBoxedPoint)point).Change(4, 4);
            Console.WriteLine(point);

            ((IChangeBoxedPoint)o).Change(5, 5);
            Console.WriteLine(o);

            Console.Read();
        }

        interface IChangeBoxedPoint
        {
            void Change(Int32 x, Int32 y);
        }

        struct Point : IChangeBoxedPoint
        {
            public Int32 x;
            public Int32 y;

            public void Change(int x, int y)
            {
                this.x = x;
                this.y = y;
            }

            public override string ToString()
            {
                return string.Format("({0},{1})", x, y);
            }
        }
    }
}

写出程序运行结果。

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

using System.IO;

namespace DotNetFramework
{
    class Program
    {
        static void Main(string[] args)
        {
            Point point = new Point();

            point.x = point.y = 1;
            // 显示（1，1）
            Console.WriteLine(point);

            point.Change(2, 2);
            // 显示（2，2）
            Console.WriteLine(point);

            object o = point;
            // 显示（2，2）
            Console.WriteLine(o);

            // 在堆栈上改变临时的point
            ((Point)o).Change(3, 3);
            // 显示（2，2）
            Console.WriteLine(o);

            // 对point执行装箱，然后改变以装箱对象，最后将之丢弃
            ((IChangeBoxedPoint)point).Change(4, 4);
            // 显示（2，2）
            Console.WriteLine(point);

            // 改变以装箱对象，并显示其内容
            ((IChangeBoxedPoint)o).Change(5, 5);
            // 显示（5，5）
            Console.WriteLine(o);

            Console.Read();
        }

        interface IChangeBoxedPoint
        {
            void Change(Int32 x, Int32 y);
        }

        struct Point : IChangeBoxedPoint
        {
            public Int32 x;
            public Int32 y;

            public void Change(int x, int y)
            {
                this.x = x;
                this.y = y;
            }

            public override string ToString()
            {
                return string.Format("({0},{1})", x, y);
            }
        }
    }
}