?int sum,flag;
??? switch(month)
??? {
?????? case 1:sum=0;break;
?????? case 2:sum=31;break;
?????? case 3:sum=59;break;
?????? case 4:sum=90;break;
?????? case 5:sum=120;break;
?????? case 6:sum=151;break;
?????? case 7:sum=181;break;
?????? case 8:sum=212;break;
?????? case 9:sum=243;break;
?????? case 10:sum=273;break;
?????? case 11:sum=304;break;
?????? case 12:sum=334;break;
?????? default:printf("一年當中只有十二個月");break;
?????? }
?????? sum=sum+day;
?????? if(year%400==0||(year%4==0&&year%100==0)?
??????????? flag=1;
?????? else
??????????? flag=0;
??????? if(flag==1&&month>2)
??????? sum++;
??????? printf("%d年%d月%d日是該年的第%d天",year,month,day,sum);

?return 0;
}