C# implements the program code of USB interface.

Namespace ConsoleApplication1
{Class Program
{Static Void Main(string[] Args)
{
USB Usb;Usb = New UDisk();// inserts U dishUsb.OutputFile();// from U dish numerate fileUsb.InputFile();// past U dish keep a fileUsb.Dispose();// pulls out U dish
Console.WriteLine("" );Usb = New MDisk();// inserts mobile hard diskUsb.OutputFile();// numerates from mobile hard disk fileUsb.InputFile();// keeps a file toward mobile hard diskUsb.Dispose();// pulls out mobile hard disk
Console.WriteLine("" );Usb = New MP4();// inserts MP4Usb.OutputFile();// numerates from MP4 fileUsb.InputFile();// keeps a file toward MP4Usb.Dispose();// pulls out MP4
Console.ReadKey();
}

/ / USB interfacePublic Interface USB: IDisposable
{Void OutputFile();// numerates fileVoid InputFile();// keeps a file
}

/ / U dishPublic Class UDisk: USB
{Public UDisk()
{
Console.WriteLine("U dish be all set. . . .. ) ;
}Public Void OutputFile()
{
Console.WriteLine(" from U dish numerate file " );
}Public Void InputFile()
{
Console.WriteLine(" past U dish write file " );
}Public Void Dispose()
{
Console.WriteLine("U dish already was pulled out " );
}
}

/ / mobile hard diskPublic Class MDisk: USB
{Public MDisk()
{
Be all set of Console.WriteLine(" mobile hard disk. . . .. ) ;
}Public Void OutputFile()
{
Console.WriteLine(" numerates from mobile hard disk file " );
}Public Void InputFile()
{
Console.WriteLine(" writes file " ); toward mobile hard disk
}Public Void Dispose()
{
Console.WriteLine(" mobile hard disk already was pulled out " );
}
}

/ / MP4Public Class MP4: USB
{Public MP4()
{
Console.WriteLine("MP4 be all set. . . .. ) ;
}Public Void OutputFile()
{
Console.WriteLine(" numerates from MP4 file " );
}Public Void InputFile()
{
Console.WriteLine(" writes file " ); toward MP4
}Public Void Dispose()
{
Console.WriteLine("MP4 already was pulled out " );
}
}
}
}