static void Main(string[] args) { var prices = new[] { new ProductPrice("A", 1.25M, new VolumePrice(3M, 3)), new ProductPrice("B", 4.25M), new ProductPrice("C", 1.00M, new VolumePrice(5M, 6)), new ProductPrice("D", 0.75M) }; var terminal = new PointOfSaleTerminal(prices); terminal.Scan("A"); terminal.Scan("A"); terminal.Scan("A"); terminal.Scan("A"); terminal.Scan("C"); terminal.Scan("D"); Console.WriteLine(terminal.PrintReceipt()); Console.WriteLine($"Total Price: {terminal.CalculateTotal()}"); }