int AgeYears(Date date1, Date date2) {
	int sign=1;
	if (date1 > date2) sign = -1;
	int age_years = sign*(date2.year - date1.year);
	int month_dif = sign*(date2.month - date1.month)
	if ((month_dif < 0)||((month_dif == 0)&&(sign*(date2.day - date1.day) < 0))) age_years--;
	return age_years;
}