Overloading of dereferencer and node iterator

[Thesar]

I am creating a queue, and i have some overloading i need to get working.

I start with my two classes:

typedef Person Item;
class Node;
class QIterator
{
private:
	Node *node;
public:
	QIterator(); // Förvald konstruktor
	QIterator(Node *n); // Initieringskonstruktor
	Item &operator*() const;
	QIterator &operator++(); // prefix ++i
	QIterator operator++(int); // postfix i++
	bool operator!=(const QIterator &qi) const;
};
//---------------------------------------------------------------------------
class QList
{
private:
	Node *first, *last;
public:
	QList() :first(nullptr), last(nullptr) {};
	~QList() {};
	void enque(Item item);
	bool deque(Item &item);
	bool del(Item item);
	bool isEmpty()const;
	QIterator begin()const { return QIterator(first); }
	QIterator end() const { return QIterator(nullptr); }
};


class Node
{
public:
	Node *next;
	Item data;
	Node(Node *n, Item newData) : next(n), data(newData) {}
};

One of my problems is to overload the dereferencer.

The prototype is:
Item &operator*() const;

The definition:

Item &QIterator::operator*() const 
{
	Item item = node->data;

	return item;
}

This one should return a reference to the Node member data, on which the current node pointer points at.

I cant get it to work

[TheIdeasMan]

Hi,

The item variable goes out of scope at the end of the function. It is technically an xvalue (eXpiring value). One can extend it's lifetime by return a const reference:

const Item &QIterator::operator*() const 
{
Item item = node->data;

return item;
}

By the way please use code tags: select your code and press the <> button on the formatting menu on the right of screen.

Good Luck !!

[ne555]

return node->data;

[Thesar]

I got it working woth the <> button, thank you.

What it the difference between

const Item &QIterator::operator*() const 
{
Item item = node->data;

return item;
}

and

QIterator &QIterator::operator++() {

	node = node->next;

	return *this;
}

And how about my other ++ operator QIterator QIterator::operator++(int)

Since it should not return a reference but only whats inside of the node that the iterator points at, would it be enough to "return this" ?