置若惘闻

struct order
        {
            public string itemName;
            public int unitCount;
            public double unitCost;
            public double SumCost()  
            {
                return unitCount * unitCost;
            }
            public string OrderInformation()
            {
                return "Order information: " + unitCount + " " + itemName + " " + "item at $" + unitCost + " each, total cost $" + SumCost();
            }
        }
 
        static void Main(string[] args)
        {
            order bill;
            bill.itemName = "Milk";
            bill.unitCount = 10;
            bill.unitCost = 0.3;
            Console.WriteLine(bill.SumCost());
            Console.WriteLine(bill.OrderInformation());
            Console.ReadKey();
        }