输出某个日期是该年的第几天

/*
	Author: WuWei 
	Date: 05/11/16 23:42
	Description: 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;
}