I have been trying to compile this code but all my attempts failed, can someone please explain to me what's the meaning of randvar in this code:

int upper_range = 255;
  for(int i=0; i<256; i++){
        upper_range -= i;
        int delete_list_entry(temp_head, randvar);
  }

From the provided code, I can't offer more than

int delete_list_entry(temp_head, randvar);

should be

delete_list_entry(temp_head, randvar);

I get the impression there's a little confusion between how to declare/define functions and how to call them.

Also, if delete_list_entry returns a value, I'd also ask why you're ignoring it.