Laravel添加到购物车数量

I have update my cart session with no quantity currently. Mean i click on add to cart id increment the value and quantity goes 1 and its works for me.

On my controller

$cart->add($product, $product->id);

Default Code With cart model

public function add($item, $id){
    $storedItem = ['qty' => 0, 'price' => $item->price, 'item' => $item];
    if($this->items) {
        if(array_key_exists($id, $this->items)) {
            $storedItem = $this->items[$id];
        }
    }
    $storedItem['qty']++;
    $storedItem['price'] = $item->price * $storedItem['qty'];
    $this->items[$id] = $storedItem;
    $this->totalQty++;
    $this->totalPrice += $item->price;
}

its works fine for default one quantity.

But i add a third parameter quantity the cart item total is goes wrong i know it always incremented with one every time because i add ++ in my both quantity but it goes the totalQty wrong.

Please help