friend function of the class can't access to its private vector;

Question

I have the following declaration:

friend ostream& operator<<(ostream&,const List&);

and I have the following definition:

ostream& operator<<(ostream& out,const List& item) {
    vector<List::Employee>::const_iterator It;
    for (It=item.employees.begin();It!=item.employees.end();It++) {}
}

Employee is a structure of mine own,and employees is a private vector of Employee in class List. The compiler gives me the following errors:

std::vector<List::Employee,std::allocator<List::Employee>> List::employees is private

any ideas how to solve it?

where is the friend declaration? remember friendship is not inherited... — Doug T., Dec 03 '12 at 04:32
A *method* ?? Do you mean the class decl (the List class, btw)? — WhozCraig, Dec 03 '12 at 05:29
Yes,I decl the output operator as a friend function of the class(in the public) — Qiaosen Huang, Dec 03 '12 at 05:42
Which class is the friend declaration in - is it in the `List` class or the `Employee` class? — user93353, Dec 03 '12 at 05:46
Why C tag is used here? I can't find anything related to C in the question — Krishnabhadra, Dec 03 '12 at 05:52
@user1831226 fwiw, the public location of the friend'ing has nothing to do with it. Friending is a boolean condition; either you are, or you aren't. the only thing left then is the decl in the class does not match the decl of the free-operator function. check them again. — WhozCraig, Dec 03 '12 at 06:00
Can you reproduce the error in a small, self-contained program? — n. m. could be an AI, Dec 03 '12 at 07:08
So is the friend declaration in the `List class` or in the `Employee structure`? — user93353, Dec 03 '12 at 07:16

score 0 · Answer 1 · answered Dec 03 '12 at 06:03

0

The friend declaration should be inside the List class definition.

class List{
    ...
    friend ostream& operator<<(ostream&,const List&);
};

answered Dec 03 '12 at 06:03

zen-cat

425
2
9

Pretty sure that was what the OP meant when he said "...It's declared in the List class". – WhozCraig Dec 03 '12 at 06:06

friend function of the class can't access to its private vector;

1 Answers1