CHAPTER 131 — Unordered Linked List

Preliminary version. Changes are likely.

Data structures are vital to programming and linked lists are vital to data structures. This chapter discusses how a linked list can be implemented in an object. The LinkedList class of this chapter implements an unordered linked list of integers. The things you can do with this linked list of integers could just as easily be done with an ArrayList of Integers, but more complex data structures are hard to do using arrays.

The essential concepts of this chapter are how a data structure is built by linking nodes together, and how the methods that maintain the data structure may be members of an object that represents the entire structure.

In this chapter, the integers in the list may be in any order. Methods attach new nodes to the list without regard to order. An ordered linked list keeps its data in ascending (or descending) order. The insert method for such a list must find the correct place in the list for a new node. This is the subject of the next chapter.