> Ok. So is the derived class object also a base class object? Exactly > the same one?
You can always cast derived object to an instance of its base class, that is the interest of inheritance, actually one of the most basic principles of object-oriented programming. Think of casting as changing point of view; a doctor can see his friend as his friend, or as a concrete patient, or as an instance of generic mankind species, depending on what he needs. That happens when you cast. static_cast<FrictPhys*>(..) says that now you want to see that object as a pointer to FrictPhys (heaven with you if the cast is invalid -- dynamic_cast will give you NULL which you can check, static_cast will skip that check and give you a valid but nonsense pointer, which will most likely lead to crash). The pointer is always exactly the same. You can try pointer comparison on some data member: FrictPhys* fp=static_cast<FrictPhys*>(i->interactionPhysics.get()); NormShearPhys* nsp=static_cast<NormShearPhys*>(i->interactionPhysics.get()) assert(&(fp->shearForce)==&(nsp->shearForce)); (When you access shearForce, internally you access the NormShearPhys where it is declared; it is the compiler's job to resolve that). HTH, Vaclav _______________________________________________ Mailing list: https://launchpad.net/~yade-dev Post to : [email protected] Unsubscribe : https://launchpad.net/~yade-dev More help : https://help.launchpad.net/ListHelp
