Question

I’m trying to do the following without too much special case code to deal with invalidated POSITIONs etc:

What’s the best way to fill in the blanks?

void DeleteUnreferencedRecords(CAtlMap<Record>& records) {    for(____;____;____)    {       if( NotReferencedElsewhere(record) )       {         // Delete record         _______;       }    } } 

Answer 1

According to this:

http://msdn.microsoft.com/en-us/library/0h4c3zkw(VS.80).aspx

RemoveAtPos has these semantics

Removes the key/value pair stored at the specified position. The memory used to store the element is freed. The POSITION referenced by pos becomes invalid, and while the POSITION of any other elements in the map remains valid, they do not necessarily retain the same order.

The problem is that the order can change — which means that GetNext() won’t really continue the iteration. It looks like you need to collect the POSITIONs you want to delete in one pass and delete them in the next. Removing a POSITION does not invalidate the other POSITION objects