title: Appending to a linked list, code doesn't always work
body: <pre><code>void AppendList (Node *new_node, Node *head) {
      Node *walker = head;
      while (walker-&gt;next != NULL)
          walker = walker-&gt;next;
      walker-&gt;next = new_node;
  }
  </code></pre>
  
  <p>When appending to a linked list, our professor wrote this code in the slides, and he said that this won't always work. Can you please explain to me why?</p>