Access Modifiers | PHP Tutorial

In the PHP programming language, every property and method of a class can have access modifiers which control their accessibility in the entire program.

There are three access modifiers in PHP:

Public
Protected
Private

Below is a table for a better understanding of the access modifiers:

Class Member Access Specifier	Access from own class	Accessible from derived class	Accessible by Object
Private	Yes	No	No
Protected	Yes	Yes	No
Public	Yes	Yes	Yes

Public

Public property or method can be accessed by any code whether that code is inside or outside of that class. If a property or method is declared public, then it can be accessed anywhere from the code.

Example:

<?php
class Employee {
  public $name;
}
 
$emp1 = new Employee();
$emp1->name = 'Harry'; 
?>

Protected

Protected property or method can only be accessed within the class and by the classes derived from that class.

Example:

<?php
class ParentClass {
    protected $parentMsg = "protected parent attribute<br>";
    protected function parentDisplay() {
        echo "protected parent method<br>";
        echo $this->parentMsg;
    }
}
class ChildClass extends ParentClass {
    protected $childMsg = "Protected Child attribute.<br>";
    public function childDisplay() {
        echo "Public Child method to display protected parent members:<br>";
        $this->parentDisplay();
    }
}
$child = new ChildClass();
$child->childDisplay();
?>

Output:

Public Child method to display protected parent members:
protected parent method
protected parent attribute

Private

The Private property or method can only be accessed within the class. If it is called outside of the class, then it will throw an error.

Example:

<?php
class Employee {
  public $salary;
 
  private function set_salary($n) { // a private function
    $this->salary = $n;
  }
}
 
$emp1 = new Employee();
$emp1->set_salary('300'); // It will throw error as It cannot Access the Private Function
?>