using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace ConsoleApplication1{    public interface IPrints    {        double a { set; }        void Print();        void PrintPreview();    }    public class IPrint    {        static void Main()        {            Console.WriteLine("Plesas select printer：");            string printerName = Console.ReadLine();            IPrints printer = null;            if (printerName == "HP")            {                printer = new test();            }            else if (printerName == "IBM")            {                printer = new IBMPrint();            }            else if (printerName == "Epsom")            {                printer = new EpsomPrint();            }            printer.PrintPreview();            Console.ReadKey();            printer.Print();            Console.ReadKey();            test aa = new test();            aa.testt();            Console.ReadKey();        }    }    public class HPPrint : IPrints    {        public double a { get; set; }        public void PrintPreview()        {            Console.WriteLine(a.ToString());        }        public void Print()        {            Console.WriteLine("this is HP Printer");        }    }    public class test : HPPrint    {        double zB = 0;        public double B        {            set{zB=value;}            get { return zB; }        }        HPPrint hp = new HPPrint();        public void testt()        {            zB = 10;            hp.a = 123;            hp.a += zB;            hp.PrintPreview();        }    }    public class IBMPrint : IPrints    {        public double a { get; set; }        public void PrintPreview()        {            Console.WriteLine("this is IBM Printer");        }        public void Print()        {            Console.WriteLine("this is IBM Printer");        }    }    public class EpsomPrint : IPrints    {        public double a { get; set; }        public void PrintPreview()        {            Console.WriteLine("this is Epsom Printer");        }        public void Print()        {            Console.WriteLine("this is Epsom Printer");        }        public void PrinSt()        {            Console.WriteLine("this is Epsom Printer");        }    }}