If I were to create a base class called base and derived classes called derived_1, derived_2 etc... I use a collection of instances of the base class, then when I retrieved an element and tried to use it I would find that C++ thinks it's type is that of the base class, probably because I retrieved it from a std::vector of base. Which is a problem when I want to use features that only exist for the specific derived class who's type I knew this object was when I put it into the vector.

So I cast the element into the type it is supposed to be and found this wouldn't work.

(derived_3)obj_to_be_fixed;

And remembered that it's a pointer thing. After some tweaking this now worked.

*((derived_3*)&obj_to_be_fixed);

Is this right or is there for example an abc_cast() function that does it with less mess?