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 namespace ConsoleApplication1 {     class Program     {         static void Main(string[] args)         {             USB usb;             usb = new UDisk();//插入U盘             usb.OutputFile();//从U盘读出文件             usb.InputFile();//往U盘写入文件             usb.Dispose();//拔出U盘             Console.WriteLine("");             usb = new MDisk();//插入移动硬盘             usb.OutputFile();//从移动硬盘读出文件             usb.InputFile();//往移动硬盘写入文件             usb.Dispose();//拔出移动硬盘             Console.WriteLine("");             usb = new MP4();//插入MP4             usb.OutputFile();//从MP4读出文件             usb.InputFile();//往MP4写入文件             usb.Dispose();//拔出MP4             Console.ReadKey();         } 
        //USB接口         public interface USB : IDisposable         {             void OutputFile();//读出文件             void InputFile();//写入文件         } 
        //U盘         public class UDisk : USB         {             public UDisk()             {                 Console.WriteLine("U盘准备就绪...");             }             public void OutputFile()             {                 Console.WriteLine("从U盘读出文件");             }             public void InputFile()             {                 Console.WriteLine("往U盘写入文件");             }             public void Dispose()             {                 Console.WriteLine("U盘已被拔出");             }         } 
        //移动硬盘         public class MDisk : USB         {             public MDisk()             {                 Console.WriteLine("移动硬盘准备就绪...");             }             public void OutputFile()             {                 Console.WriteLine("从移动硬盘读出文件");             }             public void InputFile()             {                 Console.WriteLine("往移动硬盘写入文件");             }             public void Dispose()             {                 Console.WriteLine("移动硬盘已被拔出");             }         } 
        //MP4         public class MP4 : USB         {             public MP4()             {                 Console.WriteLine("MP4准备就绪...");             }             public void OutputFile()             {                 Console.WriteLine("从MP4读出文件");             }             public void InputFile()             {                 Console.WriteLine("往MP4写入文件");             }             public void Dispose()             {                 Console.WriteLine("MP4已被拔出");             }         }     } } 
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