7 将0值作为枚举的默认值

枚举类型在声明是的默认值是0：

        static Week week; 
        public static void Main(string[] args)
        {
            Console.WriteLine(week);
            Console.ReadLine();
        }
        enum Week
        {
            Monday=1,
            Tuesday,
            Wednesday,
            Thursday,
            Friday,
            Saturday,
            Sunday
        }

输出为：0

 Week看书有8个值了，所以应该始终为枚举的0值指定默认值。