下列程序的运行结果为【 】。 enum weekday {sun=7,mon=1,tue,wed, thu, fri,sat}; main ( ) { enum weekday workday,week end; int i,a[8]; workday=tue; week end=sun; printf ('/ntueday=%d sunday=%d; ',workday, week_end); workday=sun+tue; week_end= (enum weekday)3; printf ('tueday=%d sunday=%d; ',workday, weekend); a [sun]=sun; a [mon]=mon; a [tue]=rue; a [wed]=wed; a [thu]=thu; a [fri]=fri; a [sat]=sat; for(i=l;i<=7;i++) printf('%d ',a[i]); }