c++ factory

factory.cpp

#include <iostream>
#include <vector>

class GameState
{
public:
	static GameState* create(int choice);	
	virtual void invoke() = 0;
};

class Menu : public GameState
{
public:
	void invoke() { std::cout << "menu invoke\n"; }
};

class Tuner : public GameState
{
public:
	void invoke() { std::cout << "tuner invoke\n"; }
};

class Game : public GameState
{
public:
	void invoke() { std::cout << "game invoke\n"; }
};

GameState* GameState::create(int choice)
{
	if (choice == 1)
		return new Menu;
	if (choice == 2)
		return new Tuner;
	if (choice == 3)
		return new Game;
}

int main()
{
	int choice;
	std::vector<GameState*> states;
	while (true)
	{
		std::cin >> choice;
		if (choice == 0)
			break;
		states.push_back(GameState::create(choice));
	}
	for (auto s : states) s->invoke();
	for (auto s : states) delete s;
	return 0;
}