100 Programming Quiz Questions & Answers 2026

Computer Science Fundamentals — 25 Questions

1. What is an algorithm? (Step-by-step procedure for solving a problem)
2. What is a data structure? (Organized format for storing and accessing data)
3. What is Big O notation? (Describes time/space complexity of algorithms as input grows)
4. What is O(1) complexity? (Constant time — does not depend on input size)
5. What is O(n) complexity? (Linear time — grows proportionally with input)
6. What is O(n²) complexity? (Quadratic time — grows with square of input)
7. What is a stack? (Last In, First Out (LIFO) data structure)
8. What is a queue? (First In, First Out (FIFO) data structure)
9. What is a linked list? (Chain of nodes where each node points to the next)
10. What is a binary tree? (Tree where each node has at most two children)
11. What is recursion? (Function that calls itself until a base case is reached)
12. What is a hash table? (Data structure using key-value pairs with hash function for fast lookup)
13. What is binary search? (Divides sorted list in half repeatedly — O(log n))
14. What is a bubble sort? (Repeatedly swaps adjacent elements — simple but inefficient O(n²))
15. What is a quicksort? (Efficient divide-and-conquer sorting — avg O(n log n))
16. What is a graph? (Nodes connected by edges — represents networks)
17. What is DFS? (Depth-First Search — explores as far as possible before backtracking)
18. What is BFS? (Breadth-First Search — explores level by level)
19. What is dynamic programming? (Solving complex problems by breaking into overlapping subproblems)
20. What is a greedy algorithm? (Makes locally optimal choices at each step)
21. What is a mutex? (Mutual Exclusion lock — prevents simultaneous access to shared resource)
22. What is a deadlock? (Two processes waiting for each other indefinitely)
23. What is garbage collection? (Automatic memory management — reclaims unused memory)
24. What is a compiler? (Translates high-level code to machine code)
25. What is an interpreter? (Executes code line by line without prior compilation)

OOP Concepts — 20 Questions

1. What are the four pillars of OOP? (Encapsulation, Inheritance, Polymorphism, Abstraction)
2. What is encapsulation? (Bundling data and methods — hiding internal implementation)
3. What is inheritance? (Child class inherits properties/methods from parent class)
4. What is polymorphism? (Same interface, different implementations — method overriding/overloading)
5. What is abstraction? (Hiding complexity; showing only essential features)
6. What is a class? (Blueprint/template for creating objects)
7. What is an object? (Instance of a class with state (attributes) and behavior (methods))
8. What is a constructor? (Special method called when object is created)
9. What is method overriding? (Subclass provides specific implementation of a parent method)
10. What is an interface? (Contract defining methods a class must implement)
11. What is a design pattern? (Reusable solution to common software design problem)
12. What is the Singleton pattern? (Ensures class has only one instance)
13. What is the Factory pattern? (Creates objects without specifying exact class)
14. What is the Observer pattern? (One-to-many dependency — notifies observers of state changes)
15. What is MVC? (Model-View-Controller — architectural pattern separating concerns)
16. What is the difference between an abstract class and an interface? (An abstract class can have implemented methods; an interface typically cannot)
17. What is method overloading? (Defining multiple methods with the same name but different parameters)
18. What is a static method? (A method that belongs to the class rather than any instance)
19. What is composition in OOP? (Building complex objects by combining simpler objects, as opposed to inheritance)
20. What is the difference between "is-a" and "has-a" relationships? ("Is-a" describes inheritance; "has-a" describes composition)
21. What is a getter/setter method used for? (Controlled access to read or modify private class attributes)
22. What is the Strategy pattern? (Defines a family of interchangeable algorithms encapsulated as objects)
23. What is the Decorator pattern? (Adds new behavior to objects dynamically without altering their structure)
24. What does "DRY" stand for in software engineering principles? (Don't Repeat Yourself)

Web & Database Concepts — 25 Questions

1. What does HTML stand for? (HyperText Markup Language)
2. What does CSS stand for? (Cascading Style Sheets)
3. What is HTTP vs HTTPS? (HTTP = unsecured; HTTPS = HTTP + SSL/TLS encryption)
4. What is REST? (Representational State Transfer — architectural style for web APIs)
5. What is SQL? (Structured Query Language — for relational databases)
6. What is a SELECT statement? (Retrieves data from a database table)
7. What is a JOIN in SQL? (Combines rows from two or more tables based on a related column)
8. What is NoSQL? (Non-relational databases — like MongoDB, Redis, Cassandra)
9. What is an API? (Application Programming Interface — allows apps to communicate)
10. What is JSON? (JavaScript Object Notation — lightweight data interchange format)
11. What is Git? (Distributed version control system for tracking code changes)
12. What is Docker? (Platform for containerizing applications for consistent deployment)
13. What is cloud computing? (Delivering computing services over the internet)
14. What is a CDN? (Content Delivery Network — servers distributed globally for faster content delivery)
15. What is latency? (Time delay between request and response)
16. What is a primary key in a database table? (A unique identifier for each record in a table)
17. What is a foreign key? (A field referencing the primary key of another table, linking records)
18. What is database normalization? (Organizing data to reduce redundancy and improve integrity)
19. What is an index in a database, used for performance? (A structure that speeds up data retrieval at the cost of extra storage)
20. What does CRUD stand for in web development? (Create, Read, Update, Delete)
21. What is AJAX used for in web development? (Sending and receiving data asynchronously without reloading the page)
22. What is a cookie in web browsing? (A small piece of data stored by a website on the user's browser)
23. What is server-side rendering (SSR)? (Generating HTML content on the server before sending it to the browser)
24. What is a load balancer used for? (Distributing incoming network traffic across multiple servers)
25. What does "responsive design" mean in web development? (A layout that adapts to different screen sizes and devices)

Software Development Practices — 25 Questions

1. What is version control used for? (Tracking and managing changes to code over time)
2. What is a "commit" in Git? (A saved snapshot of changes to the codebase)
3. What is a "branch" in Git? (An independent line of development within a repository)
4. What is a "pull request"? (A request to merge code changes from one branch into another, often reviewed by others)
5. What is unit testing? (Testing individual components or functions in isolation)
6. What is integration testing? (Testing how different modules or components work together)
7. What is CI/CD? (Continuous Integration/Continuous Deployment — automating testing and release of code changes)
8. What is "debugging"? (The process of finding and fixing errors in code)
9. What is technical debt? (The implied cost of additional rework caused by choosing a quick, suboptimal solution)
10. What is Agile development? (An iterative approach to software development emphasizing flexibility and collaboration)
11. What is a "sprint" in Agile/Scrum methodology? (A fixed time period for completing a set amount of work)
12. What is "pair programming"? (Two developers working together at one workstation)
13. What is a "code review"? (The process of examining code written by others before it's merged)
14. What is "refactoring"? (Restructuring existing code without changing its external behavior)
15. What is an IDE? (Integrated Development Environment — software for writing and debugging code)
16. What is a "bug" in software? (An error or flaw causing unexpected program behavior)
17. What is "open source" software? (Software whose source code is publicly available for anyone to view, modify, and distribute)
18. What does "frontend" refer to in web development? (The user-facing part of an application, e.g. UI)
19. What does "backend" refer to in web development? (The server-side logic, databases, and infrastructure)
20. What is a "full-stack developer"? (A developer skilled in both frontend and backend development)
21. What is "scalability" in software systems? (The ability of a system to handle increased load efficiently)
22. What is "documentation" in software development? (Written material explaining how code or systems work)
23. What is a "dependency" in software projects? (External code or libraries that a project relies on to function)
24. What is a "merge conflict" in version control? (When changes from different branches can't be automatically combined)
25. What is the purpose of a "README" file in a code repository? (To provide an overview and instructions for the project)
26. What is "semantic versioning" (e.g. 2.1.0)? (A versioning scheme indicating major, minor, and patch changes)