Go to the previous, next section.

Stacks

Stacks are declared as an "abstract" class. They are currently implemented in any of three ways.

VStack

implement fixed sized stacks via arrays.

XPStack

implement dynamically-sized stacks via XPlexes.

SLStack

implement dynamically-size stacks via linked lists.

All possess the same capabilities. They differ only in constructors. VStack constructors require a fixed maximum capacity argument. XPStack constructors optionally take a chunk size argument. SLStack constructors take no argument.

Assume the declaration of a base element x.

Stack s; or Stack s(int capacity)

declares a Stack.

s.empty()

returns true if stack s is empty.

s.full()

returns true if stack s is full. XPStacks and SLStacks never become full.

s.length()

returns the current number of elements in the stack.

s.push(x)

pushes x on stack s.

x = s.pop()

pops and returns the top of stack

s.top()

returns a reference to the top of stack.

s.del_top()

pops, but does not return the top of stack. When large items are held on the stack it is often a good idea to use top() to inspect and use the top of stack, followed by a del_top()

s.clear()

removes all elements from the stack.

Go to the previous, next section.