Post Office Box Analogy
The concept of a linked list can be explained by a simple analogy to real-world post office boxes. Suppose Alice is a spy who wishes to give a codebook to Bob by putting it in a post office box and then giving him the key. However, the book is too thick to fit in a single post office box, so instead she divides the book into two halves and purchases two post office boxes. In the first box, she puts the first half of the book and a key to the second box, and in the second box she puts the second half of the book. She then gives Bob a key to the first box. No matter how large the book is, this scheme can be extended to any number of boxes by always putting the key to the next box in the previous box.
In this analogy, the boxes correspond to elements or nodes, the keys correspond to pointers, and the book itself is the data. The key given to Bob is the head pointer, while those stored in the boxes are next pointers. The scheme as described above is a singly linked list (see below).
Read more about this topic: Linked List, Basic Concepts and Nomenclature
Famous quotes containing the words post office, post, office, box and/or analogy:
“A demanding stranger arrived one morning in a small town and asked a boy on the sidewalk of the main street, “Boy, where’s the post office?”
“I don’t know.”
“Well, then, where might the drugstore be?”
“I don’t know.”
“How about a good cheap hotel?”
“I don’t know.”
“Say, boy, you don’t know much, do you?”
“No, sir, I sure don’t. But I ain’t lost.””
—William Harmon (b. 1938)
“To the old saying that man built the house but woman made of it a “home” might be added the modern supplement that woman accepted cooking as a chore but man has made of it a recreation.”
—Emily Post (1873–1960)
“I had many problems in my conduct of the office being contrasted with President Kennedy’s conduct in the office, with my manner of dealing with things and his manner, with my accent and his accent, with my background and his background. He was a great public hero, and anything I did that someone didn’t approve of, they would always feel that President Kennedy wouldn’t have done that.”
—Lyndon Baines Johnson (1908–1973)
“If you like to make things out of wood, or sew, or dance, or style people’s hair, or dream up stories and act them out, or play the trumpet, or jump rope, or whatever you really love to do, and you love that in front of your children, that’s going to be a far more important gift than anything you could ever give them wrapped up in a box with ribbons.”
—Fred M. Rogers (20th century)
“The whole of natural theology ... resolves itself into one simple, though somewhat ambiguous proposition, That the cause or causes of order in the universe probably bear some remote analogy to human intelligence.”
—David Hume (1711–1776)