public static void ShowOrdersPriceInterval(ref RestaurantManager restaurantManager) { Console.WriteLine("Enter the first price:"); string firstPriceStr = Console.ReadLine(); double firstPrice; while (!double.TryParse(firstPriceStr, out firstPrice) || firstPrice < 0) { Console.WriteLine("Error! Enter the price correctly!"); firstPriceStr = Console.ReadLine(); } Console.WriteLine("Enter the second price:"); string secondPriceStr = Console.ReadLine(); double secondPrice; while (!double.TryParse(secondPriceStr, out secondPrice) || secondPrice < 0) { Console.WriteLine("Error! Enter the price correctly!"); secondPriceStr = Console.ReadLine(); } List <Order> orderPrice = restaurantManager.GetOrdersByPriceInterval(firstPrice, secondPrice); foreach (var item in orderPrice) { Console.WriteLine($"No: {item.No}\nTotal Amount: {item.TotalAmount}\nDate: {item.Date}\nCount: {item.OrderItems.Count}"); } }