This PDF on “Different Applications of Stack Data Structure” is created for university and engineering students who are studying Data Structures and Algorithms (DSA). The stack is a linear data structure that follows the Last In, First Out (LIFO) principle, and it plays a fundamental role in both academics and real-world computing. In this document, students will find clear explanations of how stacks are used in expression evaluation and conversion between infix, postfix, and prefix notations, as well as in managing function calls and recursion through call stacks. It also covers practical applications like solving backtracking problems such as mazes and N-Queens, implementing undo and redo operations in text editors, checking balanced parentheses and syntax in compilers, handling memory management through stack frames, performing depth-first search in graphs, and carrying out operations such as string reversal and palindrome checking. This resource is especially valuable for students pursuing B.Tech, B.Sc (CS/IT), BCA, MCA, and related courses under universities like MAKAUT and others. It helps learners strengthen their theoretical foundation, prepare effectively for exams, lab work, and coding interviews, and gain insight into how stacks are applied in real-world computer science and system design.

1. Different Applications
of Stack Data Structure
Data Structures and Algorithms
PCC-CS301
BY AINDRILA HALDAR
DEPARTMENT OF COMPUTER SCIENCE
AND ENGINEERING
MAULANA ABUL KALAM AZAD
UNIVERSITY OF TECHNOLOGY,
WEST BENGAL

2. Introduction
AINDRILA HALDAR 2
A Stack is a linear data structure that holds a linear, ordered
sequence of elements. It is an abstract data type. A Stack works on
the LIFO (Last In First Out) process, i.e., the element that was
inserted last will be removed first. To implement the Stack, it is
required to maintain a pointer to the top of the Stack, which is the
last element to be inserted because we can access the elements only
on the top of the Stack.
In real-time applications, stacks are crucial for tasks like managing
function calls, memory allocation, expression evaluation, task
scheduling, managing program flow, maintaining history, and
implementing undo functionality.

3. Applications-I
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▪ Function Call Management:
Compilers and interpreters use a call stack to manage function calls during
program execution. Each time a function is called, its state (local variables,
return address) is pushed onto the stack. When the function completes, its
state is popped, and execution returns to the caller. This is fundamental for
handling nested function calls and recursion.

4. Applications-II
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▪ Expression Evaluation and Conversion:
Stacks are crucial for evaluating arithmetic expressions, especially when dealing with different
notations like infix, postfix, and prefix. They help in managing operator precedence and operand
processing. Stacks are also used in converting expressions from one notation to another (e.g., infix
to postfix).

5. Applications-III
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▪ Undo/Redo Functionality:
Many applications, such as text editors and graphic design software, implement undo/redo
features using stacks. Each action performed is pushed onto an "undo" stack. To undo, the last
action is popped and reversed. A "redo" stack can store undone actions to allow re-applying them.

6. Applications-IV
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▪ Browser History Navigation:
Web browsers utilize a stack to manage the history of visited URLs. When a new page is visited, its
URL is pushed onto the stack. The "Back" button functionality is implemented by popping the
current URL and navigating to the previously visited URL at the top of the stack.
▪ Backtracking Algorithms:
Algorithms that explore multiple paths to find a solution, like Depth-First Search (DFS) in graphs
or maze-solving algorithms, often employ stacks to keep track of the current path and backtrack
when a dead end is reached. The current state is pushed onto the stack, and if a path proves
unfruitful, states are popped to explore alternative routes.

7. Applications-V
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▪ Delimiter Checking:
Stacks are used to validate the proper nesting and balancing of delimiters (parentheses, braces,
brackets) in programming languages or mathematical expressions. Opening delimiters are pushed
onto the stack, and when a closing delimiter is encountered, the corresponding opening delimiter is
popped. If the stack is empty at the end, and all delimiters are matched, the expression is balanced.
▪ Reversing Data:
Due to its LIFO nature, a stack can be effectively used to reverse the order of elements in a list,
string, or other data structures. Elements are pushed onto the stack, and then popped to retrieve
them in reverse order.

8. Conclusion
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In conclusion, the stack's LIFO nature proves invaluable in scenarios where elements need to be
processed in a specific, controlled order. Its widespread use across diverse domains, from
compilers and interpreters to user-facing applications, highlights its importance in building
efficient, reliable, and scalable software systems. Mastering the stack and understanding its
applications is crucial for effective problem-solving in computer science

9. AINDRILA HALDAR 9