2. Linked list insertion
Head

3. Linked list insertion
Node n = new Node();
Head n

4. Linked list insertion tmp
Assume tmp points to the node before the place that we want to enter our new node.
tmp
Head n

5. Linked list insertion
n.setNext(tmp.getNext());
Tmp
Head n

6. Linked list insertion
tmp.setNext(n);
Tmp
Head n

7. Inserting at the head node
This time we cannot get a pointer to the node before the place we want to enter our new node! So inserting at the head is a special case.
Head n
n.setNext(head);

8. Inserting at the head node
We don't need a tmp pointer here.
Head n
head = n;

9. Inserting at the tail node
Inserting at the end is not a special case! We still need a tmp pointer pointing to the node before (ie the last node).
Tmp
Head n

10. Inserting at the tail node
And then, as before…
Tmp
Head n
n.setNext(tmp.getNext());
Note this just sets n's pointer to null.

11. Inserting at the tail node
And then, as before…
Tmp
Head n
tmp.setNext(n);

12. What happens to tmp and n?
They are local variables, so they will disappear as soon as the insert method returns.
Head

13. Recap Create the new node Should it go at the head?
If yes insert it using the method above
If not find the node before the place it should go and insert using the method shown
Head

14. Linked Lists over Arrays
No size limit
Can expand as you need
Easy to add nodes anywhere
Sequential access only, no direct access
Head