oop - PHP Setup Object-oriented classes correctly? -

i've been told have create config.php file hold of classes.

for example let's have 3 classes.

class 1: house

class 2: mycar

class 3: road

and in config.php call them:

$house = new house();  $mycar = new mycar();  $road = new road(); 

and include config.php file in every page, example index.php.

but now, want extend class road.

i can't include config.php in class? or include other' class file in while included in config.php.

is wrong way of setup classes?

how can extend classes without having errors.

do have create new object everytime?

example:

instead of including config.php ill this:

/**  * index.php  **/ include("class/house.class.php");  $class = new house();  echo $class->echome("hey"); 

and in every file same, creating new objects, can extend specific classes when needed?

function autoload($class) {     if (is_file($file = 'www/content/includes/class/'.$class.'.php')) {         require_once($file);     } }  spl_autoload_register('autoload'); 

include following code in config.php file. make sure include config file in every file want load classes.

make sure file has same name class calling. example

$house = new house(); 

would require class filename house.php

start each class file with

<?     class house {          function something() {          }      }