Classes and Inheritance

Class definition

A class describes a new type of object and bundles together the methods needed to work with objects of that type. Here is an analogy: a class is like a cake recipe, while objects are the cakes you can make by following the recipe.

Defining a class

The syntax for defining a class is

class ClassName(superclass):
 variable and method definitions

Introduction to inheritance

Every class (except the object class) has a superclasssuperclass, and it inherits variables and methods from that superclass. That is, all variables and methods defined in (or inherited by) the superclass are available to the new class.

For example, you might define a class Person with the variables name and age and a method greet. Every object of this type will have its own copies of those variables, and its own reference to the greet method. If you then create a class Customer as a subclass of Person, every object of type Customer will have its own name and age variables and a greet method. Plus, it will have whatever additional variables and methods you declare in Customer (for example, a list of purchases).