void add_days(year_t *year, month_t *month, day_t *day, int days);
void add_months(year_t *year, month_t *month, int months);
void add_days(year_t *year, month_t *month, day_t *day, int days);
void add_months(year_t *year, month_t *month, int months);
int get_mins(date_t *start, date_t *end);
int compare(date_t *a, date_t *b);
int same_day(date_t *a, date_t *b);
int get_mins(date_t *start, date_t *end);
int compare(date_t *a, date_t *b);
int same_day(date_t *a, date_t *b);