I've two n00b questions concerning the praxis of writing source code:
1. I've understood that the source files can either have the file extension .h or .c, but when should I use which extension?
2. I've got an idea for a game engine and want to use some kind of metadata publishing (XML for example) for doing the levels, characters etc. My question is: how to make the engine understand XML? or should I use any other form of metadata instead of XML? or perhaps I should use python or lua as scripting language -- but isn't that difficult? I want the program to be cross-platform.
Thanks in advance for answers, ideas and comments!