Classes and objects are powerful OOP concepts - and PHP4 supportsthem too. This article explains some basic OO entities (including classes,constructors and extensibility) with examples of a table builder and aguestbook.
Now that you've got the concepts straight, let's take a look at the nitty-gritty of a class definition.
// this is where the properties are defined
// this is where the functions are defined
// code goes here
Every class definition begins with the keyword "class",
followed by a class name. You can give your class any name that strikes your fancy, so long as it doesn't collide with a reserved PHP word. A pair of curly braces encloses all class variables and functions, which are written as you would normally code them.
In order to create a new instance of a class, you need to use the "new" keyword, and assign the newly-created object to a PHP variable.
$his = new Automobile;
In English, the above would mean "create a new object of
class Automobile and assign it to the variable $his".
You can now access all the methods and properties of the class via this variable.