Often, due to the data structure, nodes may only be linked to from a single other node. This makes it very important to consider how you implement modifying or removing nodes from a data structure.

If you inadvertently remove the single link to a node, that node’s data and any linked nodes could be “lost” to your application. When this happens to a node, it is called an orphaned node.

Examine the nodes in the diagram. node_c is only linked to by node_b. If you would like to remove node_b but not node_c, you can’t simply delete the link from node_a to node_b.

The most straightforward method to preserve node_c would be to change the link in node_a to point to node_c instead of node_b. However, some data structures may handle this in a different manner.