设计模式之简单工厂

来源：互联网发布：php 去除数组重复元素编辑：程序博客网时间：2024/06/09 22:12

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace ConsoleApplication1{    class Program    {        static void Main(string[] args)        {            Operation oper;            oper = OperationFactory.createOperate("+");            oper.NumberA = 1;            oper.NumberB = 2;            double result = oper.GetResult();        }    }    public class Operation     {        private double _numberA;        private double _numberB;        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()        {            double result = 0;            result = NumberA * NumberB;            return result;        }    }    public class OperationDiv : Operation    {        public override double GetResult()        {            double result = 0;            if (NumberB == 0)                throw new Exception("除数不能为0。");            result=NumberA/NumberB;            return  result;        }    }    public class OperationFactory    {        public static Operation createOperate(string operation)        {            Operation oper=null;            switch(operation)            {                case "+":                    oper=new OperationAdd();                    break;                case "-":                    oper=new OperationSub();                    break;                case "*":                    oper=new OperationMul();                    break;                case "/":                    oper=new OperationDiv();                    break;            }            return oper;        }    }}

工厂 OperationFactory:
方法createOperation是Operation类型，定义了一个Operation类型的变量oper，
根据operation:"+"、"-"、"*"、"/"，实例化（继承父类Operation）OperationAdd、OperationSub、OperationMul、OperationDiv
oper=new OperationAdd();

客户端:
定义Operation类型的变量oper;
oper = OperationFactory.createOperate("+");
决定oper实例化OperationAdd,

double result = oper.GetResult();
直接调OperationAdd的GetResult方法：
public class OperationAdd : Operation
{
public override double GetResult()
{
double result = 0;
result = NumberA + NumberB;
return result;
}
}

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