It’s infuriating to read published sample code that’s wrong. Sometimes code given in books is not even syntactically correct. I’ve wondered why publishers didn’t have a way to verify that the code at least compiles, and maybe even check that it gives the stated output.
Dave Thomas said in recent interview that his publishing company, The Pragmatic Programmers, does just that. Authors write in a logical mark-up language and software turns that into a publishable form, compiling code samples and inserting the output. Sample code from one of their books is more likely to work the first time you type it in than code from other publishers.