alternative to virtual typedef - c++

Question

I have an interface IEnumerable for template classes of List<>, Array<> and Dictionary<>. I was hoping to use typedef to get their templated types T.
I was hoping to do the following.
class IEnumerable
{
public:
virtual typedef int TemplateType;
}
And then override in inherited member, but you cant make a virtual typedef. So is there any other way that i could get the type of an unknown template class (IEnumerable is not template)?

Answer 1

Well, here is what is discussed in the comments in case somebody with the same question later finds this.
Basically, you want to do something similar to C#'s List<>, Array<>, IEnumerable and IEnumerator. However, you don't want to have to create a generic parent class Object because it may mean that you'll need to dynamic_cast every time.
Additionally, you don't want to make IEnumerable a template because you don't want to have to know the type when using the collection.
In fact, with C++11, you can make IEnumerable a template and not have to know the type by using the implicit type keyword auto, which is the C++11 equivalent of c#'s var keyword.
So to do this, what you can do is:
template <class T>
class IEnumerable {
public:
virtual IEnumerator<T> getEnumerator() = 0;
// and more stuff
}
then
template <class T>
class List : public IEnumerable<T> {
public:
virtual IEnumerator<T> getEnumerator() {
return ListEnumerator<T>(this);
}
}
and
template <class T>
class ListEnumerator : public IEnumerator<T> {
public:
T getNext(); // or something to this effect
// and more stuff
}
Finally, when it comes to using it, you can do:
List<int> myList;
auto i = myList.getEnumerator();
int z = i.getNext()+1;