What is a Stack?

A stack is a linear data structure in which an element may be inserted or deleted only at one end called the top of the stack. Stack uses a variable called top which indicates the topmost element in the order stack. Applications of Stack is the main topic that we are going to read very clearly.

Smart data structures and dumb code works a lot better than the other way around.
Eric S. Raymond

What is push and pop in the stack?

Inserting an element in the stack is called pushing known as push () operation. Deleting an element from the stack is called popping known as pop() operation. A stack is used in the data structure.

The Application of Stack

The application of stack are given described below

1. To convert and evaluate expressions (postfix, prefix & infix).

a. Application of Stacks in Conversions

Stack has an important role in the conversions of postfix and prefix expression. The characters of the infix are scanned and proceed for stack operation. If the scanned character is an operator and if the stack is empty, the operator is stored in the stack otherwise precedence of an operator is compared to the operator in the stack and proceeds to output expression. The process of postfix and prefix conversion is also taken place in the same way but it has a single stack that contains the converted substring and finally the converted expression.

b. Application of Stacks in Evaluation

Prefix and postfix expression can be evaluated faster than infix expression. Evaluation of expressions like infix, postfix, and prefixes can be done by scanning one character from the left (in postfix) and from the right (in the prefix). The set of the first popped elements to the first operand is evaluated and the result is then transferred to the stack but in infix expression, the precedence of the operator and brackets rule should be followed.

2. To perform the Undo Sequence.

The undo sequence is created by keeping all recent changes in the stack. While pushing a change in stack previous change is blocked by the recent change and the recent change will stay at the top of the stack. When we use undo, we call the pop operation which removes the recent change which stays at the top of the stack and utilizes it in the program. Now, that the previous change comes at the top of the stack and the sequence runs in the same order. Undo sequence is considered to be the most important application of stack in all kinds of software and websites.

3. To keep the page visited history in Web browsers.

As the stack is a data structure and can be used to count the entry by saving each entry in memory. When the user entered a website the number of entry elements increases by 1 i.e. entry element=entry element+1. That the increment will be stored in the database. Every time the users enter a website the entry element increases and finally shows the overall visits on websites.

4. Uses of the stack in recursion.

If you know about recursion then just think where the recursion function stores its previous results, Obviously in the stack. The recursive function may go to an uncountable loop and for the next step, it needs the previous result. It seems like breaking the complete process into many subprocesses and solve one after another. To give the final solution it also uses the stack, it merges all solutions from the stack. 

5. Application of Stack in Tree Traversals.

We know that tree traversal is a process to pass form all the nodes of a tree. In a tree every element cannot be accessed directly, it needs a process ie. tree traversal. This process starts from the root of the tree to the nodes with the help of edges. It uses the recursive method to pass from one node to another node. So, the stack is very useful in tree traversals.

6. To check the correctness of the parentheses sequence.

The application of the stick takes an important role in parentheses ( bracket operation) operation. Elements pass through the sack and checked to parentheses put in order according to formula or rule.

7. Uses of Stack in the data structure.

The stack can be applied in the data structure by using the most important function call of the stack like pop, push, etc.

8. Used as an auxiliary data structure for implementing the algorithm.

Stack just use as the data structure it’s stores data it’s a part but we need an algorithm to process n manipulate data so the stack act as auxiliary where the algorithm is most.

Choosing appropriate data structure is very important part of any system design. Only appropriate data structure can reduce space complexity and time complexity. Stack is most used data structure in real life applications. We use stack in daily to daily activities but unaware about it. Hope this article makes you confident of all real life and practical uses of stack data structure.