[C++]状态模式

在状态模式（State Pattern）中，类的行为是基于它的状态改变的。这种类型的设计模式属于行为型模式。

在状态模式中，我们创建表示各种状态的对象和一个行为随着状态对象改变而改变的 context 对象。

C++代码如下：

// 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

// 参考大话设计模式

#include 

using namespace std;

class Work;
class FornoonState;

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

class Work {
public:
	Work();

	void setHour(int hour) {
		_hour = hour;
	}
	int getHour() {
		return _hour;
	}

	void setFinish(bool finish) {
		_finish = finish;
	}
	int getFinish() {
		return _finish;
	}

	void setState(State* state) {
		_state = state;
	}

	void getCurrentState() {
		_state->writeProgram(this);
	}

private:
	int _hour = 0;
	bool _finish = false;
	State* _state = nullptr;
};

class SleeptimeState : public State {
public:
	void writeProgram(Work* work) {
		cout << "time: " << work->getHour() << ", can not work ,need sleep" << endl;
	}
};

class GohomeState : public State {
public:
	void writeProgram(Work* work) {
		work->setFinish(true);
	}
};

class NigthtimeState : public State {
public:
	void writeProgram(Work* work) {
		if (work->getFinish()) {
			cout << "time: " << work->getHour() << ", work done, go home" << endl;
			work->setState(new GohomeState());
		}
		else {
			if (work->getHour() < 21) {
				cout << "time: " << work->getHour() << ", work very tired." << endl;
			}
			else {
				work->setState(new SleeptimeState());
				work->getCurrentState();
			}
		}
	}
};

class AfternoonState : public State {
public:
	void writeProgram(Work* work) {
		if (work->getHour() < 19) {
			cout << "time: " << work->getHour() << ", work tired." << endl;
		}
		else {
			work->setState(new NigthtimeState());
			work->getCurrentState();
		}
	}
};

class NoontimeState : public State {
public:
	void writeProgram(Work* work) {
		if (work->getHour() < 14) {
			cout << "time: " << work->getHour() << ", work hungry." << endl;
		}
		else {
			work->setState(new AfternoonState());
			work->getCurrentState();
		}
	}
};

class FornoonState : public State {
public:
	void writeProgram(Work* work) {
		if (work->getHour() < 12) {
			cout << "time: " << work->getHour() << ", work wonderful." << endl;
		} else {
			work->setState(new NoontimeState());
			work->getCurrentState();
		}
	}
};

Work::Work() {
	_state = new FornoonState();
}

int main()
{
	Work* work = new Work();

	work->setHour(8);
	work->getCurrentState();

	work->setHour(9);
	work->getCurrentState();

	work->setHour(12);
	work->getCurrentState();

	work->setHour(15);
	work->getCurrentState();

	work->setHour(17);
	work->getCurrentState();

	work->setHour(19);
	work->getCurrentState();

	work->setFinish(true);
	work->getCurrentState();

	work->setHour(21);
	work->getCurrentState();

	return 0;
}

github源码路径：https://github.com/dangwei-90/Design-Mode

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