      . 
   :

public/private/protected -      
      . 
         : public, private, protected. 
 public       . 
 private          . 
 protected           , 
      .

<?php
/**
  * Define MyClass
  */
class MyClass
{
     public $public = 'Public';
     protected $protected = 'Protected';
     private $private = 'Private';

     function printHello()
     {
         echo $this->public;
         echo $this->protected;
         echo $this->private;
     }
}

$obj = new MyClass();
echo $obj->public; // Works
echo $obj->protected; // Fatal Error
echo $obj->private; // Fatal Error
$obj->printHello(); // Shows Public, Protected and Private


/**
  * Define MyClass2
  */
class MyClass2 extends MyClass
{
     // We can redeclare the public and protected method, but not private
     protected $protected = 'Protected2';

     function printHello()
     {
         echo $this->public;
         echo $this->protected;
         echo $this->private;
     }
}

$obj2 = new MyClass2();
echo $obj->public; // Works
echo $obj2->private; // Undefined
echo $obj2->protected; // Fatal Error
$obj2->printHello(); // Shows Public, Protected2, not Private

?>


      