Chapter 21.3, Problem 21.5CP

Program Plan Intro

Stack:

• A stack is a linear data structure.
• The stack follows the order LIFO (last-in-first-out) for performing operations.
• The two main operations performed on stack are,
  • Push() – Add item to stack.
  • Pop() – Remove item from stack.

“Push()” method:

The “Push()” is a method used to insert or add an item to the stack. The element is pushed at the top of the stack.

• The “Push()” will have an item as its argument and it returns the argument which is passed.
• If the stack is full and when “push()” method is calls the push will generate “StackOverFlowException” and return.

Syntax for push operation:

STACK.push(E element)

“Pop()” method:

• The method “pop()” is used to delete an item from the stack.
• This method does not have any argument and when this method called on a stack, the element at the top of the stack is removed.
• This method will return the top element before removing it.
• If the stack is empty (its size is equal to 0) and when the “pop()” method is called pop throws the “EmptyStackException” object.

Syntax for pop operation:

  STACK.pop()