Question

I would like to change a function that displays some info about the class so that
can print to the screen or write to a file depending on the kind of stream I am passing to the function.

I would like to have a function like:

void output(int x, default (what class do I need here??) &stream=cout){
    stream << x ;
}  

What is the proper way to do that???
Thanks for the help!

Answer 1

You generally want std::ostream&. Note that most programmers would just overload operator<< rather than define a separate output() function like you’ve done.