Stacks are the linear data structure which stores data in an ordered way.The first element inserted is at the bottom and last element is at the top.It can be implemented using an array or a linked list.It is a LIFO(Last In First Out) data structure.This means that last element inserted will be first element to be removed incase of deletion operation(Fig 1,2).

Examples of Stack

Fig 1 : A Stack of Files

Fig 1 : A Stack of Files

Fig 2  : A Stack

Fig 2 : A Stack

Array Representation of Stack

In stack,the first element is at bottom(0 position) and last element at TOP position.The topmost element of stack is represented by TOP variable.MAX variable is used to store the maximum no of elements that the stack can hold(Fig 3).

Fig 3 : A Stack

Fig 3 : A Stack




Operations on Stack

Each function in a stack runs in O(1) time.

Fig 3 : Push & Pop Operation

Fig 4 : Push & Pop Operation in Stack


PEEP Operation

This operation  first checks whether the stack is empty or has some elements(if TOP == NULL) and returns the value of topmost element without deleting it from the stack.In Fig 10, PEEP operation will return 100 to user.

Screen Shot 2014-04-08 at 5.29.36 PM

Fig 10 : A Stack

Applications of Stack


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Author: Cusp2207 on April 10, 2014
Category: Computer Science, Data Structures

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