private static void applyAllDiscounts(OrderBase order) { Discount quantiyDisount1 = new QuantityBasedDiscount("Buy 3A for 130", 3, 130, "A"); Discount quantiyDisount2 = new QuantityBasedDiscount("Buy 2B for 45", 2, 45, "B"); order.AddDiscount(quantiyDisount1); order.AddDiscount(quantiyDisount2); Discount combinedDisount = new CombinedProductsDiscount("BUY C AND D FOR 30 ONLY", 30); combinedDisount.AddApplicableProducts("C"); combinedDisount.AddApplicableProducts("D"); order.AddDiscount(combinedDisount); }