32、面向对象设计模式之工厂方法模式——工厂方法对之前的例子进行改造

using System;

namespace LearnObject
{

    public class Operation {

        private double numberA = 0;
        private double numberB = 0;
        public double NumberA {
            get { return numberA; }
            set { numberA = value; }
        }
        public double NumberB { 
            get { return numberB; }
            set { numberB = value; }
        }
        public virtual double GetResult() {
            double result = 0;
            return result;
        }
    }

    public class OperationAdd : Operation {
        public override double GetResult()
        {
                double result = 0;
                result = NumberA + NumberB;
                return result;
        }
    }

    public class OperationSub : Operation {
        public override double GetResult()
        {
            double result = 0;
            result = NumberA - NumberB;
            return result;
        }
        
    }
    public class OperationMul : Operation
    {
        public override double GetResult()
        {
            return NumberA * NumberB;
        }
    }

    public class OperationDiv : Operation
    {
        public override double GetResult()
        {
            if (NumberB == 0)
            {
                throw new Exception("除数不为零");
            }
            return NumberA / NumberB;
        }
    }
    public interface IFactory {
        public Operation CreateOperation();
    }
    public class AddFactory : IFactory {
        public Operation CreateOperation() {
            return new OperationAdd();
        }
    }
    public class SubFactory : IFactory
    {
        public Operation CreateOperation() {
            return new OperationSub();
        }
    }

    public class MulFactory : IFactory {

        public Operation CreateOperation() {
            return new OperationMul();
        }
    }

    public class DivFactoru : IFactory {
        public Operation CreateOperation() {
            return new OperationDiv();
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            IFactory operFactory = new AddFactory();
            Operation oper = operFactory.CreateOperation();
            oper.NumberA = 1;
            oper.NumberB = 2;
            double result = oper.GetResult();
            Console.WriteLine("result={0}", result);
            operFactory = new MulFactory();
            oper = operFactory.CreateOperation();
            oper.NumberA = 2;
            oper.NumberB = 3;
            result = oper.GetResult();
            Console.WriteLine("mul result = {0}",result);

        }
    }
}