Is using string.length() in loop efficient?

Question

For example, assuming a string s is this:

for(int x = 0; x < s.length(); x++)

better than this?:

int length         


        

Answer 1

It depends on your C++ implementation / library, the only way to be sure is to benchmark it. However, it's effectively certain that the second version will never be slower than the first, so if you don't modify the string within the loop it's a sensible optimisation to make.