How to see if two strings are indentical.

Question

As good old structured programmer i like to see if two strings are indentical this way: (stringA == stringB) And, yes, it do what I want. But those who are into object irritated programming soon complain that other languages, like Java, will compare if it is references to the same object, instead of if they contain the same string. Soon a recomendation shows up: (String.Compare(stringA, stringB, false, System.Globalization.CultureInfo.InvariantCulture) == 0) Yes, it still do the same, but ... well ... Argument has that it has far better speed performance. I'm told that the C# compiler optimizes code for speed, and I think that this optimizer should have no problem with such simple expression, so ... eh ...?! And ... to make matters worse ... as far as I'm told ... the first takes into account if they refere to the same object, and thus evaluate very fast if they do!!! So ... What do You think is the best/smartest way of comparing for string equality, and why?

spgilmore · Answer

Nobody has any business stating which of two methods is faster until they've measured it. So measure it. Without measuring all anyone can do is speculate and theorize. I speculate that code optimization at this level should probably not be your biggest concern. Consider design and methodology first. If you have no already finished the program found a performance issue profiled it and narrowed it down to this line you are probably wasting your time. But to answer your question I theorize that if you do a String.Compare it probably first checks the references to see if they are identical and returns true if so. If not it probably JITS to a very fast native version of a string comparison routine. I would recommend for the sake of design that you use String.Compare and let it take care fo it for you even if you think you can do it faster some other way. It probably does a better job of handling things that you might not think of like encoding character width etc. Then when the 2.0 framework comes out your code will probably still be intact and you won't be stuck rewriting a string comparison routine and all the programs that use it.