Beginning Java Programming

8Handling Input and Output

WHAT YOU WILL LEARN IN THIS CHAPTER:                

• How input and output differ
• How to handle interaction with users in your programs
• How to store and load information in files

WROX.COM CODE DOWNLOADS FOR THIS CHAPTER

The wrox.com code downloads for this chapter are found at www.wrox.com/go/beginningjavaprogramming on the Download Code tab. The code is in the Chapter 8 download and individually named according to the names throughout the chapter.

So far, all the programs you’ve been writing throughout the course of this book have operated more or less on their own, without much interaction with the user at runtime, meaning that the interaction with the program happened while you were coding it, i.e. specifying all the tasks the program should perform. Once it ran, however, the program just went its course.

Interaction in programming is described as “input/output” (I/O). Of course, this communication flows in two directions, one in the form of “output,” which is information the program provides to outside parties, and the other in the form of “input,” which is information users provide to the program or information the program reads in from the outside world. It is easy to imagine a multitude of cases where such functionality could be useful. Imagine a program asking the user’s name, for instance, or a program asking if it should terminate or ignore an error when something unexpected happens. These aspects are all covered in this chapter.

Interaction ...