Private and protected works on child class. and what is polymophism

Question

<?php
class main{
  public $bob="my name bob";
  private $lee="my surname lee";
  protected $david="my caste";
       function output(){
  $output=$this->lee;
   echo $output;
}
} class second extends main{ } $obj= new second; $obj->output();

?>

the output is 'my surname lee'. how ? i am confused with private and protected.please let me understand the working of it.and what is polymorphism in php any tutorial link or example.

Answer 1

polymorphism in php is well explained here.

In one word: Polymorphism describes a pattern in object oriented programming in which classes have different functionality while sharing a common interface.

For your question: However the variable

$lee

is private, the function

function output()

is public and can be accessed outside.

And this page have more specific sinariao in the php programming language.