php-初学PHP，这段测试代码的初始化错在哪儿？怎么改？

 $number_to_guess)        $message = $_POST['guess']." is too big, Try a smaller one!";    else if($_POST['guess'] < $number_to_guess)        $message = $_POST['guess']." is too small, Try a bigger one!";    else        $message = "I am terribly confused!";    echo $_SERVER['PHP_SELF'];?>                        
        \"".$message."\"";        ?>    
    
Guess number: