static void Main(string[] args) { /* we can use Dependency Injection here to create object but for this test I have * used console application */ List <Product> productList = new List <Product>(); PromotionOrderBO order = new PromotionOrderBO(); Console.WriteLine("Please Enter total number of order:"); int orderCount = Convert.ToInt32(Console.ReadLine()); for (int i = 0; i < orderCount; i++) { Console.WriteLine("Please enter the type of product:A or B or C or D"); string type = Console.ReadLine(); Product productType = new Product(type); productList.Add(productType); } int totalPrice = order.GetTotalPrice(productList); Console.WriteLine(totalPrice); Console.ReadLine(); }