Re: Curiously Recurring Template Pattern
Zeppe wrote:
It's very different. Think about that, instead:
int main()
{
Base* d = new Derived();
func(*d);
}
That cannot work with CRTP. You probably mean Base<Derived>* d = new
Derived(); otherwise it doesn't compile ("Base" is a family of structs,
there is no type Base from which you derived, but instead you derive from
Base<Derived>).
ups! Your template approach will fail! But CRTP don't. The main
advantage of CRTP is that you can lose the reference to the real
instantiated class without losing the polymorphism.
No you cannot lose the type, that's the point (otherwise compile time
resolving of the function to call wouldnt work). The base class when
instantiated has all the knowledge about the Derived. So you cannot lose
it, you have it there all along so you need template functions as the OP
said.
This is very useful,
for example, when you want to build a heterogeneus container like:
std::vector<Base*> v;
Again impossible with CRTP.
(Notice that you may still need a virtual destructor if the container is
the owner of the objects).
Maybe you mean something different than the OP and as such I am missing your
point?
--
Dizzy