D语言枚举常量

import std.stdio;

enum Day{ 
   Sunday = 1, 
   Monday,
   Tuesday, 
   Wednesday, 
   Thursday, 
   Friday, 
   Saturday 
} 

void main() { 
   Day day; 
   day = Day.Sunday;

   if (day == Day.Sunday) { 
      writeln("The day is Sunday"); 
   } 
}