Problem using a privatly defined struct

I have this code:

Code:

---

template <class T>
class SortedList
{
private:
        struct Node
        {
                T data;
                Node* next;
        };
       
        Node* m_head;
        Node* m_current;
public:
        friend bool operator==<T>(const SortedList<T>& L1, const SortedList<T>& L2);

---

and i try to use Node in the friend function:

Code:

---

template <class T>
bool operator==(const SortedList<T>& L1, const SortedList<T>& L2)
{
        SortedList<T>::Node* head1 = L1.m_head;
        SortedList<T>::Node* head2 = L2.m_head;
        while (head1 != NULL && head2 != NULL) {
                if (head1->data != head2->data) {
                        return false;
                }
                head1 = head1->next;
                head2 = head2->next;
        }
        return (head1 == NULL && head2 == NULL);
}

---

the compiler (g++) doesn't recognize the type, although i made this function friend... i guess it's template related, but i can't find any info on how to do it with templates...

it just says:

Code:

---

../sortedlist.h:163: error: ‘head1’ was not declared in this scope
../sortedlist.h:164: error: ‘head2’ was not declared in this scope

---

anyone?

You may need to indicate that operator== is a template function:

Code:

---

    template <class T_>
    friend bool operator==(const SortedList<T_>& L1, const SortedList<T_>& L2);

---

And then you might need the typename keyword, as you normally do for types nested within templated types:

Code:

---

        typename SortedList<T>::Node* head1 = L1.m_head;
        typename SortedList<T>::Node* head2 = L2.m_head;

---

thank you!!

"typename" was what i've been looking for.

the first thing you suggested isn't necessary because i predefined operator== as a template.