C++ template for classes with static method - c++

Question

I'm currently programming a game using cocos2dx engine and I have a level manager that keeps track of the current level and the scene that needs to be loaded. I want to avoid long if statements, such as this:
Scene* scene;
if (level == 1)
{
scene = Game_Scene1::createScene();
}
else if (level == 2)
{
scene = Game_Scene2::createScene();
}
else if (level == 3)
{
scene = Game_Scene3::createScene();
}
(...)
else if (level == 10)
{
scene = Game_Scene10::createScene();
}
Director::getInstance()->replaceScene(TransitionFade::create(0.5, scene, Color3B(0,0,0)));
The screateScene() method is a static method
static cocos2d::Scene* createScene();
What could I do to "remove" the if statement? So it would look something like this:
Scene* scene = getScene(level, sceneClass::createScene());
and it would take the correct class (that is: Game_Scene1, Game_Scene2 etc.)
Is there a nice solution for such problem? The title says template but I'm not really sure if the solution for this is a template.

Answer 1

One simple solution would be to used a table of pointer functions.
You could declare your table as
typedef cocos2d::Scene *(*PtfCreateScene)();
PtfCreateScene tab[10];
tab[0] = Game_Scene1::create_scene;
tab[1] = Game_Scene2::create_scene; ...
Using this solution you can then call the associated create_scene function using level as an index. Thus avoiding the if branchings .
scene = tab[level - 1]();
You will have to check the correctness of the index to avoid out of memory access.
Hope I answered your question. Don't hesitate to ask if you need more explanation.