下列程序的运行结果为 【4】 。
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]);

简述慢性肾衰竭