输出某个日期是该年的第几天

/*Author: WuWei Date: 05/11/16 23:42Description: 给定一个日期，输出这个日期是该年的第几天*/int Getsumday(int year, int month, int day){    int months[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};    int sum, i;    //判断是否为闰年    if ((year % 400 == 0) || (year % 100 != 0 && year % 4 == 0))    {        months[1] += 1;    }    sum = 0;    for (i = 1; i < month; i++)    {        sum += months[i-1];    }    sum += day;    return sum;}