>>876
int ddiff(date *p1, date *p2) { /* バグってても知らん */
 int diff;
 if ((diff = p1->year - p2->year) == 0) {
     if ((diff = p1->month - p2->month) == 0) {
         diff = p1->day - p2->day;
     }
 }
 return diff;
}