PHP 7 Data Structures and Algorithms

Making the linked list iterable

So far, we have seen that we can traverse each node of the linked list using a while loop inside the methods. What if we need to iterate from outside using just the linked list object? It is very much possible to achieve this. PHP has a very intuitive iterator interface that allows any external iterators to iterate through an object internally. The Iterator interface provides the following methods:

• Current: Return the current element
• Next: Move forward to the next element
• Key: Return the key of the current element
• Rewind: Rewind the Iterator to the first element
• Valid: Checks whether the current position is valid

We will now implement these methods in our LinkedList class to make our object iterate through ...