Can I continue to use an iterator after an item has been deleted from std::multimap<>?

c++, multimap, stl

Solution

http://www.sgi.com/tech/stl/Multimap.html

Multimap has the important property that inserting a new element
into a multimap does not invalidate iterators that point to existing
elements. Erasing an element from a multimap also does not invalidate
any iterators, except, of course, for iterators that actually point to
the element that is being erased.

So it should look like this:

Blah::iterator iter;
for ( iter = mm.begin();iter != mm.end();)
{
    if ( iter->second == something )
    {
        mm.erase( iter++ );
        // Use post increment. This increments the iterator but
        // returns a copy of the original iterator to be used by
        // the erase method
    }
    else
    {
        ++iter;   // Use Pre Increment for efficiency.
    }
}

Also see: What happens if you call erase() on a map element while iterating from begin to end?

and

delete a specific entry in the map,but the iterator must point to the next element after the deletion

Problem

Original source

Related problems

• What happens if you call erase() on a map element while iterating from begin to end?
• What happens if you call erase() on a map element while iterating from begin to end?