Can end() be a costly operation for stl containers

Question

On https://doc-snapshots.qt.io/qtcreator-extending/coding-style.html it is recommended to write for loops like the following:

Container::iterator end = large         


        

Answer 1

If you plan to modify the collection as you iterate, you have to do it the 2nd way (end can change) - otherwise the first is theoretically a fraction faster. I doubt it would be noticeable though.