Can I have the template class' pointer as a parameter when declaring an object of that class' type in C++?

Question

Here is the code-version of the question:

   template <class T>
   class Foo
   {
       //Stuff
   }
   Foo<Foo*> object;

Compiling this gives me:

"a template argument 1 is invalid error."

My question is,

• if it is possible to do the intended action above and if so, how and why does that said method work?
• If it isn't possible, I'm guessing it's because of having a circular reference inside the template parameter itself (e.g. Foo<Foo<Foo<.....>>> but please let me know the correct reason if I'm incorrect in my thinking.

Also I tried a forward declaration of Foo, and that did not work.

Answer 1

Foo need a template argument, you can:

Foo<Foo<int>*> object;