Chapter 18, Problem 13RQE

Program Plan Intro

Stack:

A stack is type of container. It performs “Last In First Out”.

• In stack, the item which is inserted at last will be retrieved first.
• A stack can perform two operations. They are:
  • Push – Inserting an element inside a stack.
    • When the first element is pushed into the stack, the element will be at the “top” the stack. When the second element is added, the first element is pushed down and the second element will be at the top position, like this it goes on until the element which pushed at last will be at the top of the stack.
  • Pop – Deleting an element from the stack.
    • The element which is inserted at last will be deleted first.
• The elements can be inserted and retrieved at any one end of the stack.

Example: Cookies in a container.

The baker arranges the cookies one by one in a container in which the lastly inserted cookie is taken out first (pop operation) from the container.