Class inside a class C++

Question

I was writing a code with two class, one inside of the other, here i linked a small snippet with the part which troubles me
the error is the return type of the operator++() function, however i don't know how to solve it
i tried to rewrite the code without using the template on the outer class and it works..
can anyone help me?
https://code.sololearn.com/cLyQ1EYAaQ1K/?ref=app

Answer 1

type in "typename" before the overloaded operator and see if it fixes it

Answer 2

Daniele https://en.cppreference.com/w/cpp/keyword/typename

Answer 3

it works hahaha thank you! what does typename do?

Answer 4

many thanks hinanawi !