Question

I have a loop here and I want to make it run faster. I am passing in a large array. I recently heard of Duff’s Device can it be applied to this for loop? any ideas?

for (i = 0; i < dim; i++) {
    for (j = 0; j < dim; j++) {
        dst[RIDX(dim-1-j, i, dim)] = src[RIDX(i, j, dim)];
    }
}

Answer 1

Please, please don’t use Duff’s device. A thousand maintenance programmers will thank you. I used to work for a training company where someone thought it funny to introduce the device in the first ten pages of their C programming course. As an instructor it was impossible to deal with, unless (as the guy that that wrote that bit of the course apparently did) you believe in “kewl” coding.

Needless to say, I had the thing expunged from the course, ASAP.