/// <summary> /// This method subtract money from the accountBalance. This also adds to the receipt printout. Since we have a built-in summation of products, this also prevents inaccurate repeats. /// </summary> /// <param name="catering"></param> /// <param name="cateringItem"></param> /// <param name="userQuantity"></param> public void SubtractPurchase(Catering catering, CateringItem cateringItem, int userQuantity) { accountBalance -= userQuantity * cateringItem.Price; if (cateringItem.QuantityInStock - userQuantity >= 0) { cateringItem.QuantityInStock -= userQuantity; if (!catering.AllPurchasedItems.Contains(cateringItem)) { catering.PurchasedAdd(cateringItem); } } }