/* 判断某一日期是当年的第几天*/ #include"stdio.h" void main() { int n,year,month,day,month_day_sum=0,sum, month_day[13]={0,31,28,31,30,31,30,31,31,30,31,30,31}; printf ( "请输入\"年月日\"\n" ); scanf ( "%d%d%d",&year,&month,&day ); if ( year%100!=0&&year%4==0||year%400==0 ) month_day[2]=29; if ( day>31||day<1||month>12||month<1 ) printf ( "错误" ); else { for ( n=1; n<month; n++ ) month_day_sum+=month_day[n]; sum=month_day_sum+day; printf ( "是%d年的第%d天\n",year,sum ); } }