Thread: Best way to break out of loop

Originally Posted by Ducky

Thats pretty fast indeed but it makes your CPU works 100%. (50% if you got a dual core)

Now put a Sleep(1); in the loop to avoid this and the performance is gonna drop down significantly.

A 1000 tries take 2 secs.

Well when you're repeatedly telling it to sleep for 1ms, that's going to add up to a lot of time sleeping if you don't do much else. In fact the sleeping alone there has to account for at least 1 second according to how Sleep is documented, and typically more. The fact that your real code will actually be doing something useful will mean that overall it wont be spending quite as much time sleeping.

Thanks for the comments!

@iMalc "The fact that your real code will actually be doing something useful will mean that overall it wont be spending quite as much time sleeping."

Yes i didnt realize that, my bad.

@BMJ

Code:

void ShakeIt() 
{
    RECT rcWndSz;
    int iX = 0;
    int iY = 0;
    int iScreenX = GetSystemMetrics(SM_CXSCREEN);
    int iScreenY = GetSystemMetrics(SM_CYSCREEN);
    
    DWORD oldtick = GetTickCount();
    while (1)
    {
        if (GetWindowRect(hWnd, &rcWndSz))
        {
            iX = rcWndSz.left + ((rand() % 5) * ((rand() % 100) > 50 ? 1 : -1));
            iY = rcWndSz.top  + ((rand() % 5) * ((rand() % 100) > 50 ? 1 : -1));

            iX = iX > iScreenX ? iScreenX : iX;
            iY = iY > iScreenY ? iScreenY : iY;
            iX = iX < 0 ? 0 : iX;
            iY = iY < 0 ? 0 : iY;

            SetWindowPos(hWnd, NULL, iX, iY, 0, 0, SWP_NOSIZE);
            Sleep(20);
        }
        
        if ((GetTickCount() - oldtick)> 3000) break;
    }
}