php oop access modifiers

PHP - Access Modifiers

Properties and methods can have access modifiers which control where they can

be accessed.

There are three access modifiers:

public - the property or

method can be accessed from everywhere. This is default

protected - the property or method can

be accessed within the

class and by classes derived from that class

private - the property or method can

ONLY be accessed within the class

In the following example we have added three different access modifiers to

the three properties. Here, if you try to set the name property it

will work fine (because the name property is public). However, if you try

to set the color or weight property it will result in a fatal

error (because the color and weight property are protected and private):

Example

<?phpclass Fruit {  public

$name;  protected $color;  private $weight;}$mango = new Fruit();$mango->name = 'Mango'; // OK $mango->color = 'Yellow'; // ERROR

$mango->weight = '300'; // ERROR?>

In the next example we have added access modifiers to

two methods. Here, if you try to call the set_color() or the set_weight() function it will result in a fatal

error (because the two functions are considered protected and private), even if

all the properties are public:

Example

<?phpclass Fruit {  public

$name;  public $color;  public $weight;  function set_name($n) { 

// a public function (default)   

$this->name = $n;  }  protected function set_color($n) {

// a protected function   

$this->color = $n;  }  private function set_weight($n) {

// a private function   

$this->weight = $n;  }}$mango = new Fruit();$mango->set_name('Mango'); // OK

$mango->set_color('Yellow'); // ERROR$mango->set_weight('300'); // ERROR

?>