Copy constructor for doubly linked list

Question

I am writing a code for doubly linked list. Now for copy constructor which is a good way. Just copying pointers of head and tail or copying whole list to new list? Thank you.

Answer 1

Copy the whole list.

I'd say one of main purposes of copy-constructor is copying the whole list and make two independent objects.

Copy/Move the whole list to a new list to avoid unintended dangling pointers due to destructing one of copies, unintended modifications and many other problems... After copy it should have two independent copies.

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Also, since you have to write a copy-constructor, you should write:

• Destructor
• Copy assignment operator
• Move constructor
• Move assignment operator

Read Rule of five. Moreover, you can take advantages of copy-and-swap idiom.

Answer 2

I think you can read more about moveconstructor or copy constructor in C++11. For a deep copy, you need to copy the element.