Linked Lists - Building Java Programs: A Back to Basics Approach - page 950

current = current.next;

}
...

}

}

If you are working with the list [19, 8, 42, 13] and you are removing the value
from index 2, your list will look like the following:

next next next

/

next
/

data
19

data
8

data
42

data
13

front

current

To remove the value from index 2, you need to change current.next to point to
the value that comes next, which is stored in current.next.next :

public void remove(int index) {
if (index == 0) {
front = front.next;
} else {
ListNode current = front;
for (int i = 0; i < index - 1; i++) {
current = current.next;

}
current.next = current.next.next;

}

}

Now the linked list looks like this:

data
19

next data

8

next data

42

next
/

data
13

next
/

front

current

The code has properly linked around the node that stores the value 42 (which is
the value that was stored at index 2), so the list now stores the sequence of values
[19, 8, 13].
As you write methods that involve manipulating values in the middle of the list, it
becomes clear that you often end up writing the same kind of loop to position to a
particular node in the list. This is a great place to introduce a private method:

private ListNode nodeAt(int index) {
ListNode current = front;