On 05/10/2007, Neal Becker <ndbecker2@xxxxxxxxx> wrote:> Based on advice from some time back, I write algorithms to use iterators> rather than index-based loops. Often, this requires jumping through> considerable hoops.>> I'm just wondering, with current gcc loop optimizations, it this advice> still relevant?>> Is there (in general) a difference in speed for these 2 styles? What about> if the containers are multi-dimensional and loops are nested? I remember seeing that for the simple begin-to-end loop over a vector,gcc actually ends up compiling the iterator and index versions to theexact same code. In general, I'd say that if there would be a difference, the iteratorone might be faster as moving to the "next" might be simpler thandescending some data structure to an index. Of course, I have no idea how pointers versus indices affects aliasanalysis, or how much importance you'd place in the generality ofiterators. ~ Scott -- La vendetta è un piatto che va servito freddoSed quis custodiet ipsos custodes?
