# Top 20 Programming questions asked in an interview

## Top 20 Programming questions asked in an interview

Programming questions are integral part of an interview for the developer’s position. No matter which programming language you master, it is expected that you are familiar with fundamental concepts of programming.

Coding interviews mainly comprise of data structure and algorithm related questions along with logical questions. Coding interview questions are related to array, linked list, string, binary tree, and questions from algorithms. Here are 20 most commonly asked interview questions. You can easily find answers to these questions on Google to prepare yourself for the interview.

1. How is a bubble sort algorithm implemented?
2. How to print the first non-repeated character from a string?
3. How to find the first non repeated character of a given String?
4. How do you find duplicate numbers in an array if it contains multiple duplicates?
5. How do you remove duplicates from an array in place?
6. How are duplicates removed from an array without using any library?
7. How do you find the middle element of a singly linked list in one pass?
8. How do you check if a given linked list contains a cycle? How will you find initial node of the cycle?
9. How do you reverse a singly linked list without recursion?
10. How is a binary search tree implemented?
11. How do you traverse a given binary tree in preorder without recursion?
12. How do you print all nodes of a given binary tree using inorder traversal without recursion?
13. How is a merge sort algorithm implemented?
14. How is a radix sort algorithm implemented?
15. How do you swap two numbers without using the third variable?
16. How do you design a vending machine?
17. Write a program to find prime factors of an integer?
18. What is Depth First Search Algorithm for a binary tree?
19. Difference between a stable and unstable sorting algorithm?
20. What is the difference between Comparison and Non-Comparison Sorting Algorithms?