This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
How are you expected to gain access to the elements of an array other than by using their index? If you have two indices to an array, let's call them i and j, it is very easy to swap the two, with a method like this.. . . and once you have got that working it is easy to use that method to reverse the whole array. But I can't think how you are supposed to do it without using the index.