public void Shopping(ref ShoppingCart cart, ref List <Campaign> discounts, ref List <Coupon> coupons)
{
cart.applyDiscounts(discounts);
cart.applyCoupons(coupons);
DeliveryCostCalculator deliveryCostCalculator = new DeliveryCostCalculator(Constants.costPerDelivery, Constants.costPerProduct, Constants.fixedCost);
deliveryCostCalculator.calculateFor(cart);
cart.print();
}
