Which loop is faster, while or for?

Question

You can get the same output with for and while loops:

While:

$i = 0;
while ($i <= 10){
  print $i.\"\\n\";
  $i++;
};


        

Answer 1

Depends on the language and most likely its compiler, but they should be equivalent in most languages.

Answer 2

As others have said, any compiler worth its salt will generate practically identical code. Any difference in performance is negligible - you are micro-optimizing.

The real question is, what is more readable? And that's the for loop (at least IMHO).

Answer 3

It shouldn't matter which is faster. If it does matter then benchmark it using your real code and see for yourself.

The answers to this other question might be useful as well: How to write more efficient code

Answer 4

Some optimizing compilers will be able to do better loop unrolling with a for loop, but odds are that if you're doing something that can be unrolled, a compiler smart enough to unroll it is probably also smart enough to interpret the loop condition of your while loop as something it can unroll as well.