CODEWITHSUNDEEP
c++templates
Vivee
Vivee

Reputation: 23

Return template object in template member function of template class

For educational purposes I try implement something like std container. But I'm stuck on template function declaration. Need some help with syntax

Error: error C2039: 'Begin' : is not a member of 'SinglyLinkedList<T>'.

Header:

template<class T>
class SinglyLinkedList
{
public:
    typedef Iterator<T> Iterator;

    SinglyLinkedList();
    SinglyLinkedList(const SinglyLinkedList & other);
    ~SinglyLinkedList();

    bool IsEmpty() { return !m_pHead }

    void PushFront(T data);
    T & Front();
    void PopFront();
    void Clean();

    Iterator<T> Begin(); //Error
//  Iterator<T> End();
//  Iterator<T> Delete(Iterator<T> it);

private:
    Node<T> * m_pHead;
};

cpp file:

template<class T>
Iterator<T> SinglyLinkedList<T>::Begin()
{

}

EDIT:

typedef Iterator<T> Iterator;

is just typedef so i can use SinglyLinkedList::Iterator for Iterator. I have Iterator class/ It looks like this:

template<class T>
class Iterator
{
    friend SinglyLinkedList<T>;

public:
    Iterator() : m_pLinkedList(0), m_pNode(0) {}

    ~Iterator(){};

private:
    Iterator(SinglyLinkedList<T> * pLinkedList, Node<T> * pNode) : m_pLinkedList(pLinkedList), m_pNode(pNode) {}

    SinglyLinkedList<T> * GetListPtr() { return m_pLinkedList; }
    Node<T> * GetNodePtr() { return m_pNode; }

    void SetListPtr(SinglyLinkedList<T> * pList) { m_pLinkedList = pList; }
    void SetNodePtr(Node<T> * pNode) { m_pNode = pNode; }

    SinglyLinkedList<T> * m_pLinkedList;
    Node<T> * m_pNode;

public:
    //some overloaded operators

};

Upvotes: 0

Views: 1731

Answers (1)

hidrargyro
hidrargyro

Reputation: 267

The implementation of the templates members of a class, must be in the .h file, not in a separate .cpp file. Each translation unit needs to know the implementation, in this way is able to create the correct instantiation for each different templetized call.

Also, the following line will be a problem for sure

typedef Iterator<T> Iterator;

because you are using the same name of the templetized class for your typedef, and that will produce undefined behaviour.

Upvotes: 1

Related Questions