Have you ever thought about the handling of our files in operating system? Why do we contain a hierarchical file system? How do files saved & deleted under hierarchical directories? Well, we have answers to these all questions in this section through a hierarchical data structure called Trees! Even though most common form of a tree can be described as an acyclic graph, we will see in this section only rooted tree as general tree does not have parent-child relationship.

Tree is a data structure that allows you to associate with a parent-child relationship between several pieces of data and therefore allows us to arrange our data, records and files in a hierarchical fashion. Assume a Tree representing your family structure. Let us say that we begin from grandparent; then come to parent & lastly, brothers and sisters. In this unit, we will go through the fundamental tree structures first (general trees), & then go into the specific & more popular tree called binary- trees.