简单工程模式--计算机

---运算类class Operator{ 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; }}---加法类class OperatorAdd:Operator{ public override double GetResult() { return NumberB+NumberA; } }---减法类class OperatorSub:Operator{ public override double GetResult() { return NumberA-NumberB; } }---乘法类class OperatorMul:Operator{
public override double GetResult() { return NumberB*NumberA; } }---除法类class OperatorDiv:Operator{ public override double GetResult() { if(NumberB==0) { throw Exception("除数不能为0"); } return NumberA/NumberB; } }--简单工厂类public class OperatorFactory{ public static
Operator GetOperator(string operatorflag) { Operator oper=null; switch(operatorflag) { case '+':new OperatorAdd();break; case '-':new OperatorSub();break; case '*':new OperatorMul();break; case '/':new OperatorDiv();break; } return oper; }}---客户端调用Operator
oper=OperatorFactory.GetOperator(+);oper.NumberA=2;oper.NumberB=3;double result=oper.Getresult();