metaphor would be pez(rcandy dispenserwhich stores mint candies in springloaded container that "popsout the top-most candy in the stack when the top of the dispenser is lifted (see figure stacks are fundamental data structure they are used in many applicationsincluding the following figure schematic drawing of pez(rdispensera physical implementation of the stack adt (pez(ris registered trademark of pez candyinc example internet web browsers store the addresses of recently visited sites on stack each time user visits new sitethat site' address is "pushedonto the stack of addresses the browser then allows the user to "popback to previously visited sites using the "backbutton example text editors usually provide an "undomechanism that cancels recent editing operations and reverts to former states of document this undo operation can be accomplished by keeping text changes in stack the stack abstract data type stacks are the simplest of all data structuresyet they are also among the most importantas they are used in host of different applications that include many more sophisticated data structures formallya stack is an abstract data type (adtthat supports the following two methods