Issue with Overloading

Question

Can't seem to understand what's wrong in this code. I'm trying to overload the + operator so i can add these two queue class objects but it states the class in incomplete. What am i missing?

Line 40 is where my code starts

https://code.sololearn.com/cd11f8Xy8j8a/?ref=app

Answer 1

Queue constructor+(Queue &obj) ?
should be:-
Queue operator+(Queue &obj)
I haven't checked anything else yet.

Answer 2

Thanks rodwynnejones! Keyword mixup