Programming with Objects and Classes
In This Chapter
Programming with class (and with style and finesse)
Making objects from classes
Joining the exclusive “I understand classes and objects” society
Chapters 6, 7, and 8 introduce Java’s primitive types — things like
boolean. That’s great, but how often does a real-world problem deal exclusively with such simple values? Consider an exchange between a merchant and a customer. The customer makes a purchase, which can involve item names, model numbers, credit card info, sales tax rates, and lots of other stuff.
In older computer programming languages, you treat an entire purchase like a big pile of unbundled laundry. Imagine a mound of socks, shirts, and other pieces of clothing. You have no basket, so you grab as much as you can handle. As you walk to the washer, you drop a few things — a sock here and a washcloth there. This is like the older way of storing the values in a purchase. In older languages, there’s no purchase. There are only
char values, and other loose items. You put the purchase amount in one variable, the customer’s name in another, and the sales tax data somewhere else. ...