If we implemented the stack S from the previous problem with an array, as
described in this chapter, then what is the current value of the top member
variable?
Describe the output of the following series of stack operations: push(5),
push(3), pop(), push(2), push(8), pop(), pop(), push(9), push(1), pop(),
push(7), push(6), pop(), pop(), push(4), pop(), pop().