Mentor for C self study wanted

[Harald Schmalzbauer]

Hello,

I'm abaout to learn C (really learn it, not just to be able to tinker arround 
with).
So I bought a book which has some practices in each chapter.
Now I wrote the little programs and they were almost correct, but the things 
going wrog aren't explained in that book.
Probably it has to do with the compiler, at least it was the case in one 
example.

So I wanted to ask if somebody could be so kind and answer me occasional 
questions by private mail.
The first one was for example the attached code: Why does it segfault?

Thanks in advance,

-Harry

P.S. I will change comment language of course. I'm UTC -1