Under "Adding collection support to the Vector struct" it says that the vector struct started in chapter 3. Looking at the errata, that is wrong, it should be chapter 5. So far so good.

But then it is mentioned that it is possible to treat the Vector instance as an array, using indexers from chapter 3. Up to this point I haven't read anything about treating structs (or classes) as arrays. Looking at the source code I can see that it is there, but it is never mentioned in the book - at least I haven't read anything about that in the previous chapters.

Can someone explain?

Regards, Henrik

I had the exact same problem -- I think that the editors messed up here.

If you download the code for the book from the Wrox web site, you'll see in Chapter 9 that there is a file called "VectorAsCollection.cs" -- this has the indexer in it (see "public double this [uint i]"), plus a getEnumerator() method, which I think the one in chapter 3 is missing.

You'll have to go to the MS C# documentation for an explanation of indexers if you want more data -- that seems to be missing, too. I wonder if some of the text wasn't deleted by the editors when they created this "Professional" version, so that they could get more chapters in?

As a general rule, go with the code on the download site -- I have seen other errors, too, such as the code in the last 4 lines of page 187 -- they omitted the "delegate" keyword from the anonymous method when instantiating EventHandler! This won't compile without that (and the curly braces, I think?). However, there's no correction for this one in their downloadable source code -- I've submitted an errata report to Wrox. Look at the MS C# doc for info on this, too, and I think you'll see that it always has to have the delegate keyword used for these situations.

Good luck!