cout or printf which of the two has a faster execution speed C++?

Question

I have been coding in C++ for a long time. I always wondered which has a faster execution speed printf or cout?

Situation: I am designing a

Answer 1

Anecdotical evidence:
I've once designed a logging class to use ostream operators - the implementation was insanely slow (for huge amounts of data).

I didn't analyze that to much, so it might as well have been caused by not using ostreams correctly, or simply due to the amount of data logged to disk. (The class has been scrapped because of the performance problems and in practice printf / fmtmsg style was preferred.)

I agree with the other replies that in most cases, it doesn't matter. If output really is a problem, you should consider ways to avoid / delay it, as the actual display updates typically cost more than a correctly implemented string build. Thousands of lines scrolling by within milliseconds isn't very informative anyway.