O'Reilly logo

Learn Ruby the Hard Way: A Simple and Idiomatic Introduction to the Imaginative World of Computational Thinking with Code, Third Edition, Video Enhanced Edition by Zed A. Shaw

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Exercise 42. Is-A, Has-A, Objects, and Classes

Image

An important concept that you have to understand is the difference between a class and an object. The problem is, there is no real “difference” between a class and an object. They are actually the same thing at different points in time. I will demonstrate by a Zen koan:

What is the difference between a Fish and a Salmon?

Did that question sort of confuse you? Really sit down and think about it for a minute. I mean, a Fish and a Salmon are different but, wait, they are the same thing, right? A Salmon is a kind of Fish, so I mean it’s not different. But at the same time, because a Salmon is a particular ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required