[11] Stack or Queue? Linked-list with no tail...
This exercise is written in pseudo-code.
   head = null
   thompson_unix(new Node(240))
   thompson_unix(new Node(205))
   thompson_unix(new Node(110))
   x = torvalds_linux()

   thompson_unix(n) {
      if head is null
         head = n
      else 
         n.next = head
         head.next = n
   }

   torvalds_linux() {
      if head is null || list is empty
         return null
      rv = head
      head = head.next
      return rv
   }

Rename thompson_unix() and linus_torvalds() using either stack (push()/pop()) or queue (enqueue()/dequeue()) terminology.

[12] Stack or Queue? Linked-list with tail...
This exercise is written in pseudo-code.
   head = tail = null
   page_google(new Node(110))
   page_google(new Node(205))
   page_google(new Node(240))
   x = brin_google()

   page_google(n) {
      if head is null
         head = tail = n
      else
         tail.next = n
         tail = n
   }

   brin_google(n) {
      if head is null || list is empty
         return null
      rv = head
      head = head.next
      return rv
   }

Rename page_google() and brin_google() using either stack (push()/pop()) or queue (enqueue()/dequeue()) terminology.