Protected Properties in OOP in PHP

PHP also supports protected properties. They are also declared using the protected modifier. Such properties are inherited and accessible in child classes.

Let's create a parent class with a protected property containing age:

php<?php
  class User {
    protected $age;
    
    public function setAge($age) {
      $this->age = $age;
    }
    public function getAge() {
      return $this->age;
    }
  }
?>

In the child class, let's create a method that increments the age by one:

php<?php
  class Student extends User {
    public function incAge() {
      $this->age++;
    }
  }
?>

php<?php
  class User {
    private $name;
    
    public function setName($name) {
      $this->name = $name;
    }
    public function getName() {
      return $this->name;
    }
  }
  
  class Employee extends User {
    public function setName($name) {
      if (strlen($name) > 0) {
        $this->name = $name;
      }
    }
  }
?>