public int CompareTo(Vehicle other)
{
return((VehicleType == other.VehicleType &&
Make.CompareTo(other.Make) == 0 &&
Model.CompareTo(other.Model) == 0 &&
ProductionYear == other.ProductionYear &&
LicensePlate.CompareTo(other.LicensePlate) == 0) ? 0 : -1);
}