Comment by pcwalton

Really? For loops are a nightmare. Here's one from SPEC 2006:

    for (dd=d[k=0]; k<16; dd=d[++k])
    {
        satd += (dd < 0 ? -dd : dd);
    }

The problem with for loops is that they are too flexible, and so there's more opportunity for misuse. Iterator functions are less flexible, and therefore easier to read.

And this excessive flexibility doesn't even make simple things simple. Try counting down from N to 0 inclusive using unsigned ints.