Question

My problem is, that I have a class which has as an object of itself. When I try to write the assignment or copy method I end in a kind of “classception”

the shortened class:

class Node
{
public:
    Node(QString name, Node *parent = 0);
    ~Node(void);

    // copy
    Node(const Node &srcNode);
    // assignment
    Node& operator=(const Node &srcNode);

    private:

    QString name;
    QList<Node*> children;
    Node *parent;
};

and the method (just one because its almost the same)

// Copy
Node::Node(const Node &srcNode)
{
    name = srcNode.name;

    for(int i = 0; i < srcNode.children.size(); i++)
    {
        children.replace(i, srcNode.children.at(i));
    }

    // how is it done?
    parent = srcNode.parent;
}

My problem is at the last line of the method. As you can see the parent is also an object of the type Node, so I would end up in an endless loop.

How do i deep copy this class correctly?

Hope that someone can give me a hint 🙂

Regards

Answer 1

There is no infinite loop going on here because both objects are of type Node*, so the copy-constructor does not get invoked in that expression. Actions between pointers of a certain type are completely separate from actions between objects of those actual types.