Test Class for the empty() Function

class MyClass
{
  protected $values = array();

  function addValue($key, $value)
  {
    if(!empty($key)
      && !empty($value))
      $this->values[$key] = $value;
   }

   function printValues()
   {
     foreach($this->values as $key => $value)
     {
       if(!empty($key)
         && !empty($value))
         echo "'$key' => '$value'\n";
     }
   }
}

$object = new MyClass;

$object->addValue(0, 1);
$object->addValue(1, 2);
$object->addValue(2, 0);

$object->printValues();