PHP Class Problem HELP!

Hi i am creating a simple class with code below:

class classname 
    function __constructor($param) 
    echo "Constructor called with parameter $param <br />"; 

$a = new classname('First'); 
$b = new classname('Second'); 
$c = new classname(); 


I am using WAMP and using Komodo edit. However, everytime i want to view the output in my browser, nothing shows up. Can somebody tell me why??