New Cars For Old - PHP

Now that you've got the concepts straight, let's take a look at the nitty-gritty of a class definition.

<?
class Automobile
{
// this is where the properties are defined
var $colour;
var $shape;
...
// this is where the functions are defined
function start()
(
// 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.

<?
// accessing properties
$his->make = "Ferrari";
$his->colour = "Black";
// accessing methods
$his->start();
$his->accelerate(180);
?>

Again, in English,

$his->make = "Ferrari";

would mean

"assign the value Ferrari to the variable $make of this specific instance of the class Automobile", while

$his->accelerate(180);

would mean

"execute the function accelerate() with parameter 180 of this specific instance of the class Automobile".

Note the -> symbol, and the fact that the $ symbol is omitted when accessing variables of a specific class instance.

>>> More PHP Articles          >>> More By icarus, (c) Melonfire

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