#pragma once
#include <vector>

class Observer {
public:
	virtual void update() = 0;
};

class Subject {
private:
	std::vector<Observer*> observers;
public:
	// virtual void attach(Observer* obs) { observers.push_back(obs);}
	virtual void attach(Observer* obs);
	virtual void detach(Observer*);
	virtual int size();

	virtual void notify();
};