Question

I’m having a hard time getting around the pointers. I can imagine someone here can make conceptualizing the copy constructor much more intuitive. I understand that you can’t simply assign pointers to each other (shallow copy), but I’m having a hard time actually copying the objects.

Here’s a sample of my code:

class LList {
    /* stuff */

    private:
        struct node {
            node   *next;
            node   *prev;
            int    *o;
        };

        node   *first; // The pointer to the first node (NULL if none)
        node   *last;  // The pointer to the last node (NULL if none)
}

Thanks for the help!

Answer 1

When you are writing the copy constructor, X(const T& other), for an object, X, that contains a dynamically allocated T* p (probably a Node* in your case), you will likely end up writing a line like this:

p = new T(*other.p);

This creates a copy of the object being pointed to by the object you’re copying, giving you a deep copy of that object. In your case, this would end up in a recursive deep-copying of the list.