How do I write end() for a custom linked list container?

Question

I am writing a linked list for my homework assignment and I need to implement begin() and end() for my program's requirement.

Begin() is fairly easy

Node* List::begin(){return head;}

How should I implement end()?

Answer 1

You can return a NULL pointer, or if you have a custom tail node, return that. If it's a circular doubly-linked list, you can return the sentinel node.

Keep in mind that the proper way to check for the end of the list is to call List::end(), so if you've properly setup your List class, then it doesn't exactly matter what you return, as long as

Node* node = mylist.begin();
while (node != mylist.end()) { /*... loop */ }

works and you exit the while-loop when you reach the end of the list. So that main thing is that List::end() needs to return something unique that you will never encounter if you're traversing the middle of the list.