输入年月日 判断是第多少天

#include<stdio.h>

int main() {

int mon[] = { 31,28,31,30,31,30,31,31,30,31,30,31 };

int year, days,month, sum = 0;

printf("请输入年月日：");

scanf("%d %d %d", &year, &month, &days);

if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0)

mon[1] = 29;//如果是闰年，二月更新为29天

for (int i = 0; i < month-1; i++)

sum += mon[i];

printf("这是第%d天", sum + days);

return 0;

}