public function doSumAction()
 {
     $this->model->setOp1($_POST['op1']);
     $this->model->setOp2($_POST['op2']);
     $this->model->sum();
     $result = $this->model->getResult();
     require 'application/views/result.phtml';
 }
 public function doSumAction()
 {
     $model = new CalculatorModel($_POST['op1'], $_POST['op2']);
     $model->sum();
     $result = $model->getResult();
     require 'application/views/result.phtml';
 }