C++设计模式中控制反转与依赖注入浅析

#include <iostream>
#include <list>
using namespace std;
class TestCase
{
public:
	TestCase() {};
	~TestCase() {};
	virtual int test() = 0;
	void run()
	{
		switch (test())
		{
		case 1:cout << "1\ test() " << endl; break;
		case 2:cout << "2\ test() " << endl; break;
		default:
			break;
		}
	}
};
class Cases : public TestCase
{
	virtual int test() override
	{
		return 1;
	}
};
class Dases : public TestCase
{
	virtual int test() override
	{
		return 2;
	}
};
class Application
{
public:
	void registers(TestCase *cases)
	{
		testCases.push_back(cases);
	}
	void runStage()
	{
		for (auto&it : testCases)
		{
			it->run();
		}
	}
private:
	list<TestCase*> testCases;
};
int main()
{
    std::cout << "Hello World!\n";
	TestCase *case1 = new Cases();
	TestCase *dase1 = new Dases();
	Application app;
	app.registers(case1);
	app.registers(dase1);
	app.runStage();
}

class Message
{
public:
	virtual void send(string msg) = 0;
};
class phoneMessage : public Message
{
public:
	virtual void send(string msg) override
	{
		cout << "this is phone msg : " << msg.c_str() << endl;
	}
private:
};
class NotifyIterface
{
public:
	NotifyIterface(Message *obj)
	{
		message = obj;
	}
	void sendMsg(string msg)
	{
		message->send(msg);
	}
private:
	Message *message;
};
class MessageSender
{
public:
	void sender(string msg)
	{
		cout << msg.c_str() << endl;
	}
};
//非依赖注入
class Notification
{
public:
	Notification()
	{
		msgsender = new MessageSender();
	}
	void sendMsg(string msg)
	{
		msgsender->sender(msg);
	}
private:
	MessageSender *msgsender;
};
//依赖注入
class Notification2
{
public:
	Notification2(MessageSender *obj)
	{
		msgsender = obj;
	}
	void sendMsg(string msg)
	{
		msgsender->sender(msg);
	}
private:
	MessageSender *msgsender;
};
int main()
{
	//非依赖注入的写法
	Notification *notify = new Notification();
	notify->sendMsg("this is not DI");
	//依赖注入的写法，通过依赖注入的方式来将依赖的类对象传递进来，这样就提高了代码的扩展性
	MessageSender *msgobj = new MessageSender();
	Notification2 *notify2 = new Notification2(msgobj);
	notify2->sendMsg("this is DI");
	//依赖注入，改为通过接口实现
	Message *message = new phoneMessage();
	NotifyIterface *notifyIterface = new NotifyIterface(message);
	notifyIterface->sendMsg(" Iphone !");
}