Caching the end iterator - Good idea or Bad Idea?

Question

Generally speaking is it a good idea to cache an end iterator (specifically STL containers) for efficiency and speed purposes? such as in the following bit of code:

Answer 1

I often use this style for iterating containers:

// typedef std::vector Persons;
Persons::iterator it = persons.begin(), end = persons.end();
for (; it != end; ++it)
{
    Person & person = *it;
    // ...
}

Erasing an element from a vector invalidates all iterators after the erased position.

I'm not certain about the other container types. In any case I think it would be safe to assume that all iterators become invalid after an erase. If you really need very specific information then you can always look it up. I rarely need this because because of my rather conservative coding style.