Looking for more info on c++

I've spent a bit of time messing in c++, working on expanding my knowledge of the language now I've finished at uni. I wrote a bit of a windows program, then started a new project in two different IDEs and compiled them. The compiled programs then behaved differently.

There's evidently something else going on under the lid, but I've never encountered anything about these things in books on coding c++ and such. Is there any good tutorials or just general documentation that explains things in more depth?

Thanks for the help, I'll give C# a try.

I like C/C++ as a language, but there seems to be a lot going on that isn't well documented. One of the things that bothers me off the top of my head is the #ifndef #define thing. I understand why it's there, but why does the name after these things have to be in capitals? And why do all the periods in it get replaced with underscores?

I'll probably have to try and find some in-depth book or something on these things at some point, but for now I'll leave the language alone.