调试断言失败。 Expression Map迭代器不可取消

Question

I'm trying to delete objects through an iterator as shown in the code below. The program seemed to run fine on ubuntu but I'm now in visual studio and it's throwing a debug assertion failed error. Expression: Map/set iterator not dereferencable.

Any help would be much appreciated.

map<string, Booking*> bookings; // private variable

 /**
 * remove a booking from the passenger's booking map.
 * @param flightNumber string& - flight number of the booking to be removed.
 */
void Passenger::removeBooking(string& flightNumber)
{
    map<string, Booking*>::iterator it = bookings.find(flightNumber);
    bookings.erase(it);
    delete (*it).second; // <-- error occurs here
}

/**
 * add a booking to the passenger's booking map.
 * @param booking Booking& - the booking to be added.
 */
void Passenger::addBooking(Booking& booking)
{
    Booking* bookingPtr = new Booking(booking);
    bookings.insert(pair<string, Booking*>(booking.getFlightNumber(), bookingPtr));
}

/**
 * add a booking to the passenger's booking map.
 * @param flightNumber string& - flight number of the booking.
 * @param seat Seat::Type - seat type of the booking.
 * @param status Booking::Type - status of the booking.
 */
void Passenger::addBooking(string& flightNumber, Seat::Type seat, BookingStatus::Type status)
{
    Booking *bookingPtr = new Booking(flightNumber, seat, status);
    bookings.insert(pair<string, Booking*>(flightNumber, bookingPtr));
}

Answer 1

OK, now that the code has completely changed from what was originally posted...

The error is easy to spot. You're erasing the element from the map which invalidates the iterator, then you're trying to use that iterator. You should make a temporary copy of the pointer you need to delete before you erase the iterator, or just rearrange and do the delete first.

Also as suggested in the comments, you need to make sure that the iterator returned by find is valid, ie not equal to end() .

map<string, Booking*>::iterator it = bookings.find(flightNumber);
if (it != bookings.end())
{
    Booking* temp = it->second;
    bookings.erase(it);
    delete temp;
}

or

map<string, Booking*>::iterator it = bookings.find(flightNumber);
if (it != bookings.end())
{
    delete it->second;
    bookings.erase(it);
}