Programming Interview Preparation

Practise Programming Mock Interview Online
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Programming Interview Prep

1 Free Guide Here

Read this free guide below with common Programming interview questions

2 Mock Video Interview

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3 Evaluation

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Expert Tip

Follow Up After the Interview

Sending a thank-you note or email after the interview can demonstrate your continued interest in the position and appreciate the interviewer's time.

Top 15 Programming Interview Questions and Answers

Preparing for a programming interview can be a daunting task, but you can ease your nerves by practicing common questions and answers. Here are 15 programming interview questions and their answers to help you prepare.

1. What is your experience with [programming language/framework/tool]?

This question aims to assess your familiarity with the language, framework or tool the company is interested in. Be honest and specific about your experience and level of proficiency. You can give examples of projects you've worked on that used the technology in question.

2. Can you explain the difference between a stack and a queue?

A stack is a collection of items that follows the Last-In-First-Out (LIFO) principle, while a queue follows the First-In-First-Out (FIFO) principle. In simpler terms, a stack works like a stack of books or plates, while a queue works like a line of people waiting for a bus.

3. What is object-oriented programming?

Object-oriented programming (OOP) is a programming paradigm that relies on the use of objects to represent and interact with data. It is based on the principles of encapsulation, inheritance, and polymorphism. OOP allows for more modular, reusable, and maintainable code.

4. What is recursion?

Recursion is a programming technique in which a function calls itself one or more times until a specific condition is met. Recursion is often used to solve problems that can be broken down into smaller, simpler problems, such as traversing a tree, searching a graph, or computing a factorial.

5. How do you handle errors in your code?

There are several ways to handle errors in code, such as using try-except blocks for handling exceptions, logging errors to a file or database, or displaying helpful error messages to users. You can also implement automated testing and debugging to catch errors before they reach production.

6. Can you explain the difference between a variable and a constant?

A variable is a piece of data that can change its value during the execution of a program, while a constant is a value that cannot be changed once it has been defined. Constants are often used for fixed values, such as pi or the speed of light.

7. What is a design pattern?

A design pattern is a reusable solution to a common programming problem. It is a template or blueprint for solving a particular type of problem in a specific context. Examples of design patterns include the Singleton pattern, the Observer pattern, and the Factory pattern.

8. Can you explain the principles of SOLID?

The SOLID principles are a set of five design principles that help create robust, maintainable, and scalable code. SOLID stands for Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, and Dependency Inversion. These principles emphasize modularity, flexibility, and dependency management.

9. How do you optimize a database query?

Optimizing a database query involves various techniques, such as indexing, normalization, denormalization, caching, and query tuning. Indexing helps speed up query execution by creating an index on frequently queried columns. Normalization involves breaking down data into smaller, logical tables to reduce redundancy and improve data integrity. Denormalization involves adding redundant data to improve query performance. Caching involves keeping frequently accessed data in memory to avoid repeated database queries.

10. Can you explain the difference between a hash table and a binary search tree?

A hash table is a data structure that stores key-value pairs using a hash function to map keys to a specific index in an array. A binary search tree is a data structure that stores key-value pairs using a tree-based structure, where each node has two children and follows a specific ordering rule. Hash tables offer constant-time lookup and insertion, while binary search trees offer logarithmic time lookup and insertion.

11. What is a closure?

A closure is a function that has access to the variables in its surrounding environment, even after the surrounding function has returned. Closures are often used to create functions that can remember and access the state of their enclosing environment, such as setting a default value for a parameter or maintaining a counter.

12. Can you explain the difference between synchronous and asynchronous programming?

Synchronous programming involves executing code in a sequential and blocking way, where each line of code has to finish executing before the next one can start. Asynchronous programming involves executing code in a non-blocking and parallel way, where multiple tasks can be executed simultaneously. Asynchronous programming is often used in web applications to handle concurrent requests and reduce latency.

13. How do you manage version control?

Version control is the process of managing changes to code and other files over time. It involves using a version control system (VCS) to store changes, track revisions, and collaborate with other developers. Popular VCS tools include Git, SVN, and Mercurial.

14. Can you explain the difference between a monolithic architecture and a microservices architecture?

A monolithic architecture is a traditional approach to building software where all the components of an application are tightly coupled and deployed as a single unit. A microservices architecture is an innovative approach where an application is built as a collection of smaller, independent services that communicate with each other through APIs. Microservices offer benefits such as scalability, fault tolerance, and maintainability.

15. How do you approach problem-solving?

Problem-solving is a critical skill for a programmer. Some approaches to problem-solving include breaking down a problem into smaller parts, brainstorming possible solutions, testing and refining solutions, seeking feedback, and asking for help. It's critical to balance creativity, logic, and perseverance when solving problems.

With these common programming interview questions and answers, you're better equipped to ace your next programming interview. Remember to practice your responses to each question and customize them to your experience and skills.


How to Prepare for Programming Interview

If you're preparing for a programming interview, it's essential to be well-prepared. Here are some essential tips to help you perform at your best:

1. Brush up on your coding skills

  • Review fundamental coding concepts like data structures, algorithms, and object-oriented programming.
  • Practice coding exercises to help you sharpen your coding skills.
  • Review the programming language and framework related to the position you are interviewing for.

2. Research the company and the job description

  • Review the company’s website and read up on their products or services.
  • Study the job description and understand the company's expectations for the role you are applying for.
  • Prepare questions to ask the interviewer about the company, the work environment and culture, and the responsibilities of the position.

3. Prepare your resume and portfolio

  • Update your resume and highlight your most relevant skills and experiences that align with the job requirements.
  • Create a portfolio that showcases your best programming projects and shares your code on sites like GitHub.
  • Practice going through your portfolio and be prepared to explain your code and design choices in detail.

4. Practice interview questions

  • Practice common programming interview questions and be prepared to explain your approach and thought process while solving problems.
  • Practice developing clean, organized, and effective code in a limited amount of time.
  • Practice online coding challenges on sites like HackerRank or LeetCode to refine your coding skills and speed.

5. Plan your outfit and arrive early

  • Dress professionally, and make sure your clothes are appropriate for the work environment.
  • Arrive early and familiarize yourself with the company's location and parking situation.
  • Bring copies of your resume and portfolio in case the interviewer requests them.

By following these essential tips, you'll be well-prepared for your programming interview and ready to impress the interviewer with your coding skills, problem-solving abilities, and overall professionalism.

Common Interview Mistake

Oversharing or Providing TMI

Oversharing personal details or non-relevant information can distract from the conversation and may seem unprofessional. Keep the conversation focused on your qualifications and suitability for the role.