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)

Web & Database Concepts — 20 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)