Is the ranged based for loop beneficial to performance?

Question

Reading various questions here on Stack Overflow about C++ iterators and performance**, I started wondering if for(auto& elem : container) gets \"expan

Answer 1

Range-for is as fast as possible since it caches the end iterator^{[citation provided]}, uses pre-increment and only dereferences the iterator once.

so if you tend to write:

for(iterator i = cont.begin(); i != cont.end(); i++) { /**/ }

Then, yes, range-for may be slightly faster, since it's also easier to write there's no reason not to use it (when appropriate).

N.B. I said it's as fast as possible, it isn't however faster than possible. You can achieve the exact same performance if you write your manual loops carefully.