Thread: learning to work with SDKs & source code out there...

Hi all,

I'm a newbie programmer, somewhat comfortable programming my own applications from scratch in Win32API or .NET. What I'm having trouble though, is understanding and working with other people's code, like various SDKs and source code widely available on the internet. I just don't know what to do after I unzip the file.
For example, I'd download the source code of some open source application, unzip it in some directory, and notice that there's a bunch of directories, a bunch of project files, maybe a couple solution files, hundreds of .h files, hundreds of .c files and so on and so forth.
Forgive my ignorance, but what on earth am I supposed to be doing with all this? I understand that I'd need to compile something, probably, but which project or which solution am I supposed to compile? If I pick a random one and compile it, I end up with a bunch of errors I am clueless about. and then what? I'd have to figure out how the program works, but with hundreds of files floating around, where do I begin? (assuming no helpful documentation...)

I've learned to program mostly on my own, reading books and tutorials, but no books out there seem to talk about how to figure out stuff other's have written. Perhaps it's supposed to be obvious. Well, it isn't for me.
Anyhow, I know that this forum is filled with experienced programmers, and they all must have had a transition from being able to program things on their own to being able to work with stuff other's have written. So if anyone could share their experience with learning how to do this, I'd be much indebted!

From my experience, the first thing you have to do in order to understand that source code you downloaded is to fix all those errors you found when compiling. Those are usually because: A) they wrote code that was dependent for their complier; or B) the code you downloaded is a bit outdated from the libraries they're using. This is a great exercise regardless of what you're trying to do, since there really is no book or tutorial you can read to tell you how to read other peoples code. It's something you just have to get good at on your own.

The second thing to do would be focus on only what you need to accomplish. A while back, when working with the Maya API trying to export geometry, I was bombared with their scene graph, their entire object hierarchy and interface, and MEL scripting. Instead of learning about each piece and all its intricacies, I first looked for the functionality that would solve my problem (exporting vertices and animation hierarchies/frames). Of course, I had to dive into the scene graph and their object hierarchy to do that, but I started from the bottom up: figured out what I needed, then slowly kept stepping up until I can solve the problem.