private double CalculatePayForTimeCard(TimeCard card)
 {
     double overtimeHours = Math.Max(0.0, card.Hours - 8);
     double normalHours = card.Hours - overtimeHours;
     return rate * normalHours + rate * 1.5 * overtimeHours;
 }
 public void AddTimeCard(TimeCard card)
 {
     timeCards[card.Date] = card;
 }