It's very simple: Just remember the original position and sort on that when items are equal otherwise. That requires a little bit more memory so a separate stable version could be considered. But I don't think it's worth the trouble since sort() already temporarily allocates memory linear to the size of the sorted array.
/ Martin Stjernholm, Roxen IS
Previous text:
2003-04-23 16:18: Subject: sort
Martin Stjernholm had somewhat interesting ideas regarding making any unstable sort algorithm stable with a more or less cheap wrapper. I'm hoping he might comment on the subject. :)
/ Johan Sundström (folkskådare)