How to pass a value to a class method?

Question

PHP

No matter how I twist, then one error then another:

class Calculator
{
    public function add($date)
    {
        $my = trim($date);
            $D = explode(",", $my);
            
            $l = strlen($DArr[2]);
            if(1 <= $D[0] && 31 >= $D[0] && 1 <= $D[1] && 12 >= $D[1] &&  $l == 4){
                return true;
            }
            else{
                return false;
            }
    }
 
}
$class = new Calculator;
//$class->$date='12,11,2009';
$class->add(12,11,2009);

var_dump($class);

Answer 1

In add, pass the value in quotes.
And look at the standard DateTime class