模式定义

状态模式允许对象在内部状态改变时改变它的行为，对象看起来好像修改了它的类。

模式结构：

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编程实现及执行结果：

#include 
  
   
using namespace std;


class Worker;	//类的前置声明

//状态类
class State
{
public:
	virtual void doing(Worker* w){}
};
//工作状态
class WorkingState: public State
{
public:
	void doing(Worker* worker);
};
//休息状态
class SleepingState: public State
{
public:
	void doing(Worker* worker);
};
//其他状态
class OtherState : public State
{
public:
	void doing(Worker* worker);
};

//工人类
class Worker
{
public:
	Worker()
	{
		state = new WorkingState();
	}
	void setState(State* stat)
	{
		state = stat;
	}
	double getHour()
	{
		return hour;
	}
	void setHour(double hou)
	{
		hour = hou;
	}

	void requestDoing()
	{
		state->doing(this);
	}
private:
	State* state;
	double hour;
};
//各个状态doing方法的实现
void WorkingState::doing(Worker* worker)
{
	if(worker->getHour() > 8 && worker->getHour()  < 16)
		cout << "WorkingState!" << endl;
	else
	{
		worker->setState(new OtherState());
		worker->requestDoing();
	}
}

void SleepingState::doing(Worker* worker)
{
	if(worker->getHour()  >= 21 || worker->getHour()  < 5)
		cout << "SleepingState!" << endl;
	else
	{
		worker->setState(new OtherState());
		worker->requestDoing();

	}
}

void OtherState::doing(Worker* worker)
{
	if((worker->getHour() >= 5 && worker->getHour() < 8) 
			|| (worker->getHour() >= 16 && worker->getHour() < 21))
		cout << "SleepingState!" << endl;
	else if(worker->getHour() >= 21 || worker->getHour() < 5)
	{
		worker->setState(new SleepingState());
		worker->requestDoing();
	}
	else
	{
		worker->setState(new WorkingState());
		worker->requestDoing();
	}
}
//客户代码
int main()
{
	Worker* pWorker = new Worker();
	pWorker->setHour(24);
	cout << "time 24" << endl;
	pWorker->requestDoing();

	pWorker->setHour(11.5);
	cout << "time 11.5" << endl;
	pWorker->requestDoing();

	pWorker->setHour(19);
	cout << "time 19" << endl;
	pWorker->requestDoing();
	
	delete pWorker;
	return 0;
}
  

执行结果：

time24

SleepingState!

time11.5

WorkingState!

time19

SleepingState!

请按任意键继续. . .