计算日期 并判断闰年的

#include <stdio.h>
int month[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
main()
{int yy,mm,dd, days;
int i;
printf("input year:"); scanf("%d", &yy);
printf("input month:"); scanf("%d", &mm);
printf("input day:"); scanf("%d", &dd);
/* 如果大于2月，要做闰年的判断，忘了，不一定准 */
if( mm > 2 && ((year%4==0 && year%100!=0) || year%400==0) ) days = 1;
else days = 0;

/* 加上前面各整月的天数 */
for(i = 0; i < mm-1; i++) days += month[i];

/* 加上日数 */
days += dd;

printf("This is the %d day of year %d!!\n", days, yy);
}