Question

This code is supposed to append two linked lists, I totally fail to see how this code appends the two Cell Structs passed as arguments, as no manipulating is happening to the second parameter. it justs asks for the next node in the first Cell – so how can this work?

void Append(Cell *& first, Cell* second)
{
  if (first == NULL)
  {
    first = second;
  }
else {
    Append(first->next, second);
  }
}

Answer 1

The else block of the function keeps following the next pointer of first until it gets to the end of that list. That is, until first->next is NULL and the else does not get executed.

Now the base case in the if block. When first->next is NULL, it changes that pointer to point at second, which is presumably the first element in another list.

The reason there is some effect is because the first->next pointer is passed by reference. Modifying the pointer will modify the actual pointer at the end of the list, rather than just modifying a copy.