int DayOfWeek(Date date) {
return (date.Get() + 6) % 7;
}
Date operator-(Date a, int b) { Date q; q.Set(a.Get() - b); return q; }
Date operator+(Date a, int b) { Date q; q.Set(a.Get() + b); return q; }
Date operator+(int a, Date b) { Date q; q.Set(b.Get() + a); return q; }
int operator-(Date a, Date b) { return a.Get() - b.Get(); }
