In this current tutorial we will study about what is object and what is reference? how to create object in PHP, how to give reference to another object etc. In PHP a reference is an alias and an object variable does not contain the object rather it contains the identifier and it allows to access the actual object.

PHP Object and References:

It is a very common misconception about object that the terms object and reference is interchangeable. Now we must know what is actually an object and what is a reference.

Whenever an object is instantiated it occupies some memory, that memory chunk is called an object and the name or identifier which refers to that memory chunk is called a reference. But in general we call the first reference of that memory chunk as object and the objects which are used to refer the first object as reference. 

Similarly in PHP a reference is an alias and an object variable does not contain the object rather it contains the identifier and it allows to access the actual object.   

Example:

<?php

class A{

public $var=2;

}

$a=new A();

$b=$a;

$b->var=4;

echo "\$a=".$a->var."<br/>";

$c=new A();

$d=&$c;

$d->var=43;

echo "\$c=".$c->var."<br/>";

function display($obj){

$obj->var=34;

}

$e=new A();

display($e);

echo "\$c=".$e->var."<br/>";

?>

Output:

$a=4
$c=43
$c=34

 

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