计算年度第几天

/** * 输入某年某月某日，判断这一天是这一年的第几天 */public int day(int year,int month,int day){    int date = 0;       int arr[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };       if ((year % 400 == 0) || (year % 4 == 0 && year % 100 != 0)) {//闰年           arr[1] = 29;       }       for (int i = 0; i < month - 1; i++) {           date += arr[i];       }       date += day;       return date;}