<?php
class testClass
{
    // property declaration
    public $var = 'a default value';
    public static $testvar = " a testClass variable";

    // method declaration
    public function displayVar(){
        echo $this->var;
    }

    public function extClassMethods(){
        $this->bigTest(2, 3);
        $this->smallTest();
    }

    private function bigTest($num1, $num2){
        $sum = $num1 + $num2;
        echo " ".$sum." ";
    }

    private function smallTest(){
        echo "& smallTest";
    }
}

class newClass
{
    public function test(){
        // display testClass' public static $testvar value
        // Note: If E_STRICT is enabled, the next line might issue a warning
        echo testClass::$testvar;
    }
}

$instance = new testClass();
$instance->var = "Hallo";
$instance->displayVar();
$instance->extClassMethods();

$newinstance = new newClass();
$newinstance->test();
?>