'for' loop vs Qt's 'foreach' in C++

Question

Which is better (or faster), a C++ for loop or the foreach operator provided by Qt? For example, the following condition

QList

        

Answer 1

For small collections, it should matter and foreach tends to be clearer.

However, for larger collections, for will begin to beat foreach at some point. (assuming that the 'at()' operator is efficient.

If this is really important (and I'm assuming it is since you are asking) then the best thing to do is measure it. A profiler should do the trick, or you could build a test version with some instrumentation.