calloc initializes the memory with zero. calloc = clear + alloc

Presumably he has random access to the list; otherwise this problem would be impossible.

The answer is pretty simple, and we're not just going to give you the answer.

Here's a hint though: ...

message_to_network should already be a function that waits for a new message to reach the socket. I'm guessing about its implementation, but you should just need to call that function -- it will...

That doesn't involve function pointers though :-/

Mentioning function pointers must be a sign of being completely lost, since there's only a finite constant set of values a function pointer can...

I am very confused. How in the world are you going to implement a stack using function pointers?

Not to mention that his very own example is still unsafe!

http://eternallyconfuzzled.com/tuts/hashing.html

Yes. Want to know how?

It's operating system specific, but one general option is to use the 'system' procedure. Or, if you're using a Unixy operating system and want more control over how things...

= is the assignment operator, not equivalence test operator, and you probably declared a as const.

Um... yes. But not with the + operator, of course; with some specially built procedure. I don't know what you mean by 'add', either, but surely there's some way for you to write the algorithm.