4. Introduction to Classes and Objects
Nothing can have value without being an object of utility.
Your public servants serve you right.
—Adlai E. Stevenson
Knowing how to answer one who speaks, To reply to one who sends a message.
You will see something new. Two things. And I call them Thing One and Thing Two.
—Dr. Theodor Seuss Geisel
In this chapter you will learn:
• What classes, objects, methods and instance variables are.
• How to declare a class and use it to create an object.
• How to implement a class’s behaviors as methods.
• How to implement a class’s attributes as instance variables and properties.
• How to call an object’s methods to make the methods perform their tasks.
• The differences ...