状态模式

1. 一个对象的行为取决于他的状态，并且它必须在运行时刻根据状态改变他的行为。
2. 一个操作中含有庞大的多分支结构，并且这些分支决定于对象的状态。

#include "stdafx.h"
#include <iostream>
using namespace std;

class Work;
class State
{
public:
	virtual ~State(){}
	virtual void WritePrograme(Work* work) = 0;
};

class Work
{
private:
	State* Current;
	double Hour;
	bool finish = false;
public:
	~Work()
	{
		if (Current != NULL)
			delete Current;
	}
	double GetHour(){ return Hour; }
	void SetHour(double hour){ Hour = hour; }

	bool TaskFinished(){ return finish; }
	void SetFinish(bool f){ finish = f; }

	void SetState(State* s){ Current = s; }

	void WritePrograme()
	{
		Current->WritePrograme(this);
	}
};

class  SleepingState :public State
{
public:
	virtual void WritePrograme(Work* work)
	{
			cout << "睡觉时间" << endl;
	}
};

class  AfternoonState :public State
{
public:
	virtual void WritePrograme(Work* work)
	{
		if (work->GetHour() < 18)
		{
			cout << "下午时间" << endl;
		}
		else
		{
			work->SetState(new SleepingState());
			work->WritePrograme();
		}
	}
};

class  ForenoonState :public State
{
public:
	virtual void WritePrograme(Work* work)
	{
		if (work->GetHour() < 12)
		{
			cout << "上午时间" << endl;
		}
		else
		{
			work->SetState(new AfternoonState());
			work->WritePrograme();
		}
	}
};

// StatusPattern.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "Status.h"

int _tmain(int argc, _TCHAR* argv[])
{
	Work* work = new Work();
	work->SetState(new ForenoonState());
	work->SetHour(10);
	work->WritePrograme();

	work->SetHour(20);
	work->WritePrograme();

	getchar();
	return 0;
}