Is there a performance penalty for working with a vector from the standard library in C++ instead of arrays in C?
- 3suggest your benchmark your precise situation.Mitch Wheat– Mitch Wheat2009-09-19 02:36:08 +00:00Commented Sep 19, 2009 at 2:36
- @Wheat, Couldn't agree more with you.strager– strager2009-09-19 03:00:31 +00:00Commented Sep 19, 2009 at 3:00
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2 Answers
No, there's not (provided you compile with optimization so inlining can happen), provided you mean dynamically sized C "arrays" obtained with malloc.
Fixed-sized arrays in C will have the slight advantage that their address is fixed after linking (if global), or that they live directly on the stack rather than indirectly through a pointer to somewhere on the heap. I do believe there is still no performance difference; constant base addresses aren't faster than variable ones; both get loaded into a CPU register.
1 Comment
Elmue
This answer is WRONG!
The only real difference is that accesses with std::vector go through trivial functions. So long as you're using an appropriate optimization level such that those function calls get inlined, they'll be the same.
