Question

I’ve got a linked list where I save data, and a pointer to next node, Node<T>* next, like this:

template <class T>
struct Node
{
    T data;
    Node<T>* next;
};

The thing is I want to put in this a post-increment operator, so it returns the previous value of my node, but increment the reference. So if I do this

Node<int>* someNode = someList.SomeNode();
Node<int>* tmp = someNode++; 

tmp would be the original someNode value, but someNode would be someNode->next.

is it possible to put an operator in the struct? I’ve tried to, and searched how to do it, but as I don’t deal with operators I don’t know how to do.

Answer 1

You cannot add member function to basic type like pointer.

What are you trying to define is an iterator. Use wrapper class over your node pointer to succeed:

template <class T>
struct NodeIterator
{
  NodeIterator(Node<T>* current) : current(current) {}
  NodeIterator& operator ++() { current = current->next; return *this; }
  NodeIterator operator ++(int) { 
      NodeIterator retVal = *this; 
      ++(*this);
      return retVal;
  }
  T* operator-> () const { return &current->data; }   
  T& operator * () const { return current->data; }   
  Node<T>* current;
};

See std::slist<> implementation for references. Look at template<typename _Tp> struct _List_iterator. Reading STL implementation is better than many books.

Usage:

NodeIterator<T> it =  &node;
++it;
T& t = *it;