Sentinel Nodes

Last updated Nov 16, 2021 Edit Source

Sometimes, when implementing Linked List, especially Doubly Linked List, it makes our job much easier to implement sentinel nodes. Sentinel nodes are basicaly dummy nodes that are defined with the list, called header and tailer. By using these dummy nodes, our job is greatly simplified due to several reasons:

• We don’t have to implement seperately the addFirst() and addLast() method since every add operation is made between two nodes,(even in an empty list, nodes are added between header and tailer).
• The header and tailer nodes remain constant in the list.