关于C#的隐式枚举转换

隐式枚举转换允许把十进制整数0 转换成任何枚举类型，对应其它的整数则不存在这种隐式转换，下面用一个例子来具体说明本问题：

using System;
        enum Weekday{
                Sunday,Monday,Tuesday,Wednesday,Thursday,Friday,Saturday
       };

class Test
       {
               public static void Main() {
                       Weekday day;
                        day = 0;
                       Console.WriteLine(day);
               }
       }

程序的输出是

0

注意：把 day = 0 改写为 day = 1 编译器就会给出下面的错误：

Can not implictly convert type 'int' to type 'enum'