Object-Oriented Concepts for php

As Senior Web Developer, I am required to be technical lead within the team. This also means making sure the technology is understood and used correctly. With this in mind, I’ve recently noticed that many of my team-mates obviously don’t understand the underlying concepts of OOP. For this reason, I’ve prepared this short tutorial on the concepts – to be followed by more detailed posts on execution in Javascript and in PHP.

<?php
class SimpleClass
{
    // define variable
    public $var = 'a default value';

    // method declaration
    public function displayVar()
     {
     // calling value of variable using $this->var
        echo $this->var;
     }
   
}
// making object of class
$b = new SimpleClass();
// calling function using object////////////
$b->displayVar();
?> 

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
Creating an instance

<?php
$instance = new SimpleClass();// This can also be done with a variable: 
$className = 'Foo'; 
$instance = new $className();
 // Foo()?>