Foreach performance

[Lykurg]

Foreach seems to be the answer... but it makes a copy, so it needs extra memory.

Yes, but since most of the Qt classes uses implicit sharing it isn't a problem. Just make sure you use const! this will save a lot of time.
And if that is still to slow for you, use const STL-style iterators, they are the fastest. And if you think that your source code is unreadable with STL iterators, make a quick benchmark on your device and see if they are really quicker.

[spirit]

read this post, but it deals with Qt classes.