References and Aliases are Different Mechanisms (z

References and Aliases are Different Mechanisms    
Author:    zkarakaya    
Date    14/03/2001    
Aliasing and Referencing are completely different mechanisms in PHP.
If you are Java or C++ programmer, you must be careful when using
Objects created on run-time.

Lets see an example;

 
<? 
class MyClass{ 
     var $myData; 
     var $outManager; 
    cfunction MyClass($p){ 
        $this->myData=$p; 
        $this->outManager = new MyOutManager($this); 
     } 
    cfunction display(){ 
        $this->outManager->display(); 
     } 
} 
 class MyOutManager{ 
     var $refObj; 
    cfunction MyOutManager(&$obj){ 
        $this->refObj = &$obj; 
     } 
    cfunction display(){ 
        echo $this->refObj->myData; 
     } 
} 
$myvar = new MyClass(10); 
$myvar->myData = 20; 
$myvar->display(); 
?> 
 

What value be the output of this program code. Many programmer will
say "20", but this is not correct. Output is 10. Why? Because we have
created an instance of MyClass type on the right hand side of assignment
operator, and gave an initial value of 10. In the constructor of MyClass,
we have send the memory location of that newly created instance to another