My book on Java seems to suggest that in switch statements each case that isn't the default should cover an exceptional condition. What is the meaning of this and why is it recommended? Can you provide any examples to illustrate the point?
Edit: I think I got the meaning/implication of the original quote: Inputs or situations that don't meet your initial expectations almost always need to be covered, and the default case in switch statements supplies a way to do so.
I think you misunderstood what the author wrote. He said:
Including a default case focuses you on the need to process exceptional conditions.
What he meant is, you are going to add everything you are thing to the switch case, and then adding a default will guarantee that you will think about every other possibility. For instance, if you switched for animals, "cat", "dog", "pig", well, what if the user input something else? Adding a default forces you to think about that, and handle errors and exceptional cases appropriately.
