Simple Factory Mode instance

Operation class

public class operation    {        private double A = 0;        Private double b = 0;        Public double A        {            get {return A;}            set {a = value;}        }        Public double B        {            get {return B;}            set {b = value;}        }        Public virtual Double GetResult ()        {            Double rst = 0;            return rst;        }    }

Subtraction class

public class Jia:operation     {public        override double GetResult ()        {            double result = 0;            result = A + B;            return result;        }    }    public class Jian:operation     {public        override double GetResult ()        {            double result = 0;            result = A-B;            return result;        }    }    public class Cheng:operation    {public        override double GetResult ()        {            double result = 0;            result = A * B;            return result;        }    }    public class Chu:operation    {public        override double GetResult ()        {            double result = 0;            if (b==0)                throw new Exception ("divisor cannot be 0");            result = A/b;            return result;        }    }

Factory class

public class Operationfactory    {public        static operation CreateOperation (string operation)        {            Operation result = NULL;            Switch (operation)            {case                ' + ': result = new Jia ();                Case "-": result = new Jian (); break;                Case "*": result = new Cheng (); break;                Case "/": result = new Chu (); break;                Default: Break                    ;            }            return result;        }    }

Console requests

Console.Write ("Please enter the first number"); DoubleA =convert.todouble (Console.ReadLine ()); Console.Write ("Please enter a second number"); Doubleb =convert.todouble (Console.ReadLine ()); Console.Write ("Please enter operator"); stringOPR =Console.ReadLine (); Operation Opr2=operationfactory.createoperation (OPR); Opr2. A=A; Opr2. B=b; Doubleresult =OPR2.            GetResult ();            Console.WriteLine (result); Console.ReadLine ();

Simple Factory Mode instance