Why am I getting segfault when changing the signature of main?

Question

I am trying to get my feet into C, and wrote this program that displays a kb of my RAM in a random location. Here is the code, and it works fine:

#include 

        

Answer 1

Both your snippets invoke undefined behavior as you try to

1. Go out of bound (mem++;, with no allocation)
2. use uninitialized values (accessing *mem )

with the current version.

Remember, pointers do not magically inherit (or acquire) memory, you need to make a pointer point to something valid, in general.