Public And Private

Private properties and functions can be accessed or modified only in the class body.

Public members can be accessed or modified anywhere - both inside and outside the class body.

It can be understood via the following code:

<?php class Person { // set default value for id private $id = "1"; public $name; public $age; public function printData() { echo "Name: " . $this->name . "\n"; echo "Age: " . $this->age . "\n"; echo "Id: " . $this->id . "\n"; } } // create object $personObject = new Person(); $personObject->name = "John"; $personObject->age = 20; //personObject->id = "new_id"; $personObject->printData();

Output:

Name: John Age: 20 Id: 1

There are a couple of things to notice about the private property id and the public properties name and age:

• Both public and private properties can be accessed/modified in the class body: for public properties - lines 12 and 13, for private properties - line 14.
• Outside the Person class body (like the Main function) only public properties can be accessed/modified - lines 21 and 22.
• If we uncomment line 23 the code will not execute. Because a private member (id in this case) cannot be accessed/modified outside the Person class body.