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);
/* Time to string functions */
const char *month_to_str(month_t month);
const char *month_to_string(month_t month);
/* Time to string functions */
const char *month_to_str(month_t month);
const char *month_to_string(month_t month);