An Introduction to Object-Oriented Programming, 3rd Edition

Chapter 2

Abstraction

If you open an atlas you will often first see a map of the world. This map will show only the most significant features. For example, it may show the various mountain ranges, the ocean currents, and other extremely large structures. But small features will almost certainly be omitted.

A subsequent map will cover a smaller geographical region and will typically possess more detail. For example, a map of a single continent (such as South America) may now include political boundaries and perhaps the major cities. A map over an even smaller region, such as a country, might include towns as well as cities and smaller geographical features, such as the names of individual mountains. A map of an individual large city might include ...