Overriding Parent Methods in OOP in PHP

A child class can override a parent method by creating a method with the same name. Let's look at an example. Suppose we have the following parent class:

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

Let's create a method with the same name in the child class:

<?php
	class Student extends User {
		public function setName($name) {
			
		}
	}
?>

Typically, overriding parent methods is necessary to change or extend the behavior of that method. In our case, let's add a check for the name length:

<?php
	class Student extends User {
		public function setName($name) {
			if (strlen($name) > 0) {
				$this->name = $name;
			} else {
				echo 'student name error';
			}
		}
	}
?>

Let's make sure that it is the overridden method that is called. First, let's create an object of the child class:

<?php
	$student = new Student;
?>

Now let's call our method, passing a valid value to it:

<?php
	$student->setName('john');
?>

And now let's call the method, passing an invalid value to it. As a result, we will see the thrown exception:

<?php
	$student->setName(''); // error
?>

In the User class, create an age getter and setter.

In the Employee class, override the age setter and implement a check that the age is from 18 to 65 years.