简单工厂模式

1.概念解析

2.示例代码

#include<bits/stdc++.h>

using namespace std;

class Operation
{
public:
	Operation():_numberA(0), _numberB(0){ }
	
	double GetNumberA()
	{
		return _numberA;
	}
	double SetNumberA(double value)
	{
		_numberA = value;
	}
	
	double GetNumberB()
	{
		return _numberB;
	}
	double SetNumberB(double value)
	{
		_numberB = value;
	}
	
	virtual double GetResult()
	{
		double result = 0;
		return result;
	}

private:
	double _numberA;
	double _numberB;
};

class OperationAdd:public Operation
{
	double GetResult()
	{
		return GetNumberA() + GetNumberB();
	}
};

class OperationSub:public Operation
{
	double GetResult()
	{
		return GetNumberA() - GetNumberB();
	}
};

class Factory
{
public:
	static 	Operation* Create(char ioperator);
};

Operation* Factory::Create(char ioperator)
{
	Operation *oper;
	switch(ioperator)
	{
	case '+':
		oper = new OperationAdd();
		break;
	case '-':
		oper = new OperationSub;
		break;
	default:
		oper = new OperationAdd();
		break;
	}
	return oper;
}

int main()
{
	int a,b;
	char oper;
	
	while(1)
	{
		cin>>a;
		cin>>oper;
		cin>>b;
	
		Operation * op = Factory::Create(oper);
		op->SetNumberA(a);
		op->SetNumberB(b);
	
		cout<<op->GetResult()<<endl;
	}	
	
	return 0;
}

3.运行结果