Has anyone found a way to remove any item from a list as it is iterating?

Normally a loop to iterate through a linked list looks like this:

for ( it = list.begin(); it != list.end(); it++ )
{
}

If you want to be able to remove an item from the list while it is iterating, you can always do this:

it = list.begin();
while (it != list.end() )
{
	if (condition)
	{
		it = list.erase(it);
	}
	else
	{
		it++;
	}
}

But what if the code in your loop called other code that could result in the removal of the object from the list, with no way to tell it occurred? It could also result in removing other objects from the list, with no way of knowing it happened. In that case, our previous trick would not be enough to prevent any possible problems, because the code might be removing the next item in the list after we have forwarded the iterator.

Has anyone come up with a solution to this?

One solution is for the objects to mark themselves as "dead", perhaps using a flag or adding themselves (e.g. index or pointer) to a separate "dead list". The master loop can clear dead objects at a convenient time.

You can erase items from a list as your iterating it, you just need to stash the next iterator before you do stuff to the current one.

auto it = myList.begin();

while(it != myList.end())
{
    auto nextIt = it;
    ++nextIt;

    doStuffWith(it);

    it = nextIt;
}

I'm using auto to save typing but if you not got C++11 support it's easy to change.

EDIT: This wont work with vector or any other container that can cause stuff to be copied or moved around in the container.

I'm really not sure if it works, but have you tried going from the back of the list to the front?

(This worked for me once with ArrayLists in Java)

This works fine for array-based collections but once you get to more complex datastructures it can get difficult to delete anything without disrupting the iterator.

One solution is for the objects to mark themselves as "dead", perhaps using a flag or adding themselves (e.g. index or pointer) to a separate "dead list". The master loop can clear dead objects at a convenient time.