Using Both Map and List for Same Objects

Question

I\'m trying to use both a list and an unordered_map to store the same set of objects. I\'m new to C++, so still getting comfortable with iterators.

Say I have the follow

Answer 1

If what you want to do is this:

Is it possible to look up an object by key, and then generate a list iterator from the reference of the object (or from the unordered_map generator?)

Then you can take advantage of the fact that list iterators aren't invalidated on insertion or erase (unless you erase that particular iterator) and reorganize your structures like this:

std::list list;
std::unordered_map::iterator> map;

map.insert(std::make_pair(101, 
    list.insert(list.end(), t1)));
map.insert(std::make_pair(102, 
    list.insert(list.end(), t2)));
map.insert(std::make_pair(103, 
    list.insert(list.end(), t3)));

That way your map lookup gives you exactly what you want: a list iterator.