@{Item} {top()}
{Returns the item on top of the \Stack, without removing it. $O(1)$ }@

@{Item} {pop()}
{Returns the item on top of \Stack and removes it. $O(1)$}@

@{void} {push(Item& passed_item)}
{Pushes {\em passed_item} onto the top of the \Stack. $O(1)$}@

@{void} {insert(Item& passed_item)}
{Pushes {\em passed_item} onto the top of the \Stack.  This method overrides
the virtual function of the same name in \Deque.}@

@{Bool} {emptyQ()} {Is the \Stack empty? $O(1)$}@

@{void} {clear()} {Remove all the elements from the \Stack. $O(n)$}@