Algorithm efficiency

[hopesfall]

Would these functions be considered O(1) (in terms of Big-O notation)?

void Stack::pop() throw(StackException)
{
   if (isEmpty())
      throw StackException("StackException: stack empty on pop");
   else
   {  // stack is not empty; delete top
      StackNode *temp = topPtr;
      topPtr = topPtr->next;
      // return deleted node to system
      temp->next = NULL;  // safeguard
      delete temp;
   }  // end if
}  // end pop 

void Queue::enqueue(const QueueItemType& newItem)
   throw(QueueException)
{
   if (count == MAX_QUEUE)
      throw QueueException(
	 "QueueException: queue full on enqueue");
   else
   {  // queue is not full; insert item
      back = (back+1) % MAX_QUEUE;
      items[back] = newItem;
      ++count;
   }  // end if
}  // end enqueue 

If so, why? My understanding is that it would because it takes the same amount of time regardless of the size of the problem.

[elflesnoy]

First is O(1)
Second is O(1) in case 'items' as an array. Of course, it 'items' is a class object with operator[] defined the complexity can be different