classes and php

the hardest concept i've tried to understand since beginning to use php was that of classes. i'd never used a database engine but learning to use mysql, at least for the more basic functions, was a breeze. having never used oop before, classes were novel as well, but understanding the theory and why it was useful escaped me. i knew they must be powerful as "everything" is programmed using oop, but for the life of me, although i thought i understood the mechanics, i couldn't see the usefulness. then, just a few days ago, while trying to figure out how to do something with regular functions it hit me just how doing it with objects would make my job much simpler! i'm going to try to explain about them in plain english and hopefully help others like myself.

classes are nothing more than a collection of variables and functions acting on those variables. they provide a means of thinking about things in real world terms. in other words they describe an object. an object, or instance, of a class is an actual "living, breathing" structure of that class. let's say we want to describe a bicycle. a proper class of a bicycle might have the variables $pedals, $chain, $front wheel, $rear wheel, $brakes, and $handle_bars. functions of the bicycle would include stop(), accelerate(), coast(), turnleft() and turnright(). you can think of your script as the entity operating that bike. the function accelerate() could be passed an argument such as $braking_force and use that information along with the defined instance variab

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