Just a nitpicky question

Hey, I just thought of a really really nitpicky question. Does the ! operator (it is an operator, right?) make any difference in speed whatsoever? I mean, would there be any difference at all in the speed of these code examples?

Code:

---

//Clip 1
bool done = false;
while(!done)
    //stuff

//Clip 2
bool notDone = true;
while(notDone)
    //stuff

---

It doesn't really matter to me, and I know that most people would use the first code example, but just had a sudden curiosity attack.

Some speed... probably.

Noticeable... not really


However, your compiler might optimize something like that.

I'm going to say no.
In assembly that's just a difference of conditional jumps. JE vs. JNE (Jump if Equal, Jump if Not Equal)
This is what VC6 output:

Code:

---

while (!done)
0040117C  mov        eax,dword ptr [ebp-4]
0040117F  and        eax,0FFh
00401184  test        eax,eax
00401186  jne        main+48h

---

Code:

---

while (notdone)
0040117C  mov        eax,dword ptr [ebp-4]
0040117F  and        eax,0FFh
00401184  test        eax,eax
00401186  je        main+48h

---

As you can see, the only difference between the two is the different jumps. I doubt one is any faster than the other.

>I mean, would there be any difference at all in the speed of these code examples?
Before optimization, possibly, after optimization, I would be very surprised.

-Prelude

Ok, thanks :) my curiosity is satisfied.