Top 16 Coding Interview Questions and Answers

Programming is an excellent profession with a strong job outlook, competitive compensation and a dynamic work environment where you’ll solve exciting problems. These factors can make programming positions highly competitive, so knowing what to expect from a programming interview is vital for any job seeker, and can make the difference between landing the role and being overlooked. This guide will discuss some of the most common coding interview questions asked in programming interviews so you’ll be more likely to ace your interview and start your career as a programmer.

Acing the interview is just one step on the path to becoming a coder. If you haven’t yet reached this stp in the process, or you’re not ready to apply for positions quite yet, our guide on how to become a coder can help you determine where to start.

How to prepare for a coding interview

Programming interviews can be tricky — they typically involve a mix of questions about your professional background and experience, as well as technical questions designed to gauge your programming knowledge and coding ability.

Practicing your responses to common coding interview questions can help you prepare for the interview, giving you the best possible chance of getting the job.

Knowing about the most in-demand programming languages is important for anyone wanting to enter the software development field. Having hands-on experience with a few of them — such as Java, Python, C# or JavaScript — is essential, however, the best options for you will depend on the types of applications you’ll be developing on the job. Review the requirements of the position as noted in the job description and make sure you can discuss the technical differences between each coding language listed.

An image highlighting the most in-demand programming languages.

Plan on providing an overview of your professional and educational background in the interview. Need a refresher? We have a guide to computer programmer education requirements to help you prepare to discuss how you learned to code and whether you’re self-taught, earned a degree in computer science or learned through a coding boot camp.

Programming interview questions

Programming interviews can feel intimidating, but preparing can give you a better understanding of the overall process and help you feel more confident during the interview. This section will discuss some general questions you can expect and provide strategies for answering them.

1. “Can you tell me a bit about your experience?”

This is one of the most fundamental questions you should expect to answer in any coding interview — and any interview at all, for that matter. The hiring manager will want to know about your experience and how well you can work in the company’s environment.

This question is relatively open-ended, and having a good answer can feel overwhelming. One common tactic is to answer in a “present, past, future” format. Start by talking about what you’re currently doing, how your past experience prepared you for the position and what you hope to be doing in the future. Mention any relevant projects, coding languages or other factors specific to the job you’re interviewing for.

One way to answer this question using the “present, past, future” format could be:

“At the moment I’m working as a programmer for a medium-sized software development company. This is my first programming position, and I got started by working on open-source projects and completing a coding boot camp. My eventual goal is to learn more about software development and become a software engineer.”

Did you know that if you don’t have as much experience in programming as you’d like, or don’t know the necessary coding languages, there are options available to help you gain the expertise you need in just six months or less? Completing a coding boot camp provides hands-on experience in some of the industry’s most valuable technologies, including HTML/CSS, JavaScript and React.js.

2. “Can you talk about some projects you’ve worked on?”

This question allows you to discuss previous experience regarding the projects you’ve worked on in the past. If you have professional coding knowledge, you can talk through the development life cycle of some of your best projects — the planning phase, how you contributed to the project’s execution and any post-completion maintenance you were involved in.

If you don’t have professional coding experience, but you’ve worked on impressive projects on your own, consider discussing your contributions in that context. Many programmers get started by contributing to open source projects, working for clients on a freelance basis or developing their own applications. Discussing these projects in detail can help you showcase your experience without previous job experience.

An example of how to answer this question could be: “I got started by doing simple bug fixes on open source projects. This helped me learn how to work on a project with a larger group of people. One project that I’m proud of is a personal to-do list that I coded using Java. It syncs tasks across multiple applications and is customized for my coding workflows.”

If you’re just getting started and need to build up your experience, our guide to the top ten coding projects for beginners can help you come up with some ideas.

3. “Can you talk about what programming languages you use? Talk about your experience with each language and which languages you prefer.”

Questions like this one are very likely to come up in most programming interviews. As this is an experience-related question that also focuses on your personal preferences, there is no “right” answer.

One way to answer this question is to focus on your favorite programming language and mention others that you are proficient in: “I enjoy using JavaScript because it is such a flexible language that powers so much of the modern web. While JavaScript is one of the first languages I learned in order to give my portfolio website more interactivity, I’m also familiar with Java, Python and HTML/CSS.”

4. “How do you stay current with your technical knowledge?”

Programming is a constantly evolving field that requires ongoing study. This question provides an opportunity to not only discuss your commitment to lifelong learning in the field, but also how you keep up with best practices, emerging technology and new programming languages. Talk about any websites, blogs, podcasts, video creators or social media influencers you follow in the space. This is also an opportunity to discuss any side projects or online courses you’ve worked on in order to improve your skills.

Possible answers to this question might look like: “For me, one of the best ways to stay current is to use newer technologies for projects. For example, I’ve been using Julia to understand a newer language that’s getting some interest from the development community. I also read trade press and blogs about software development to stay on top of how the field is changing over time.”

5. “How do you handle working with non-technical people from different backgrounds?”

While coding roles typically focus mostly on hard programming skills (i.e. technical knowledge of programming languages and how to create applications), soft skills are also essential for computer programmers. Often, programmers have to work with non-technical people from other departments to gain buy-in and understand the needs of the organization more clearly.

When answering this question, discuss the value of interdisciplinary cooperation within an organization. You might want to discuss how gaining a non-programmer’s perspective can help improve and innovate an application. Talk about how you communicate technical concepts to non-technical people and the importance of these soft skills in the workplace. For example: “I think it’s very important for technical and non-technical roles to work together. It can be easy for developers to get lost in the development process without looking to non-technical roles for feedback. Therefore, when meeting with those from non-technical backgrounds, I try to prepare a comprehensive guide or ‘cheat sheet’ offering key terminology, helpful acronyms and other important foundational information to help them review documentation more easily, which in turn can make the entire interaction easier to navigate.”

6. “How do you get started on a new coding project?”

Software development is more than just your code knowledge — knowing how to plan, structure and execute a project is also extremely important. This question gives you a great opportunity to use the STAR method. The STAR method is a technique used for behavioral and situational interview questions. Using the technique creates a straightforward story that the interviewer can follow with all relevant information included. This will involve the following:

Begin by discussing the context around the situation or challenge. Make sure this section is specific, short and to the point and provides enough background for the interviewer to understand. For the question above, that could look like this: “During my coding studies, I was given a complex design-related group project and a relatively short window of time to complete said project. I was faced with an opportunity to exercise high-level time management, team communication and coding efficiency to ensure the project was completed properly and on time.”

Next, discuss your responsibilities in the situation. Talk about the goal you needed to achieve or the task you were given. Again, this section does not need to be long, but should communicate the task at hand. For example, “I was tasked with quickly translating data set output into intuitive data visualizations.”

After discussing the task at hand, talk about how you handled the situation or the challenge. This section can be a bit longer and more in-depth, as the actions you took will tell the interviewer more about your thought process. “Given the quick turnaround time and the need for a flexible solution, I chose to employ Python — specifically, Pandas Visualization and Plotly — to complete the task.”

To wrap up the story, talk about how things ended. Did the project go well? Were there issues that needed to be solved? Take the opportunity to discuss any positive impacts or wins generated through the project. “As a result, the data visualization piece was well-received by the stakeholders and helped them quickly make data-driven decisions. In fact, they asked me to help implement my data visualization solution on another project that was in process at the same time.”

The STAR method can be used for a wide variety of situational questions and provides a framework for discussing the specifics of previous projects you’ve completed. Consider practicing how you’ll answer questions using the STAR method so you’re ready for whatever the interview brings.

If you’re looking for more experience and a way to brush up on your coding skills, completing a coding boot camp can help you answer interview questions like these or prepare you for other types of questions.

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Java interview questions

Programming interviews frequently involve specific coding questions and challenges designed to showcase your programming skills in a real-world setting. Answering these questions requires understanding the specific technical concepts that the hiring manager is looking for, such as strings, object-oriented programming (OOP) or code design principles. Preparing for these questions can feel daunting, but below are some common examples to help you prepare.

1. “Tell me about a project where you used Java. Why was Java your language of choice?”

This question tests your knowledge of Java in relation to other programming languages. Knowing the benefits of Java over other languages showcases your ability to work in a flexible way and use different technologies depending on the task at hand.

To answer this question, discuss a project you’ve worked on in the past and the reasons why Java was a good fit. For instance, you could say: “Java is a popular language for mobile development. For example, while working on a new application with a previous employer, our team decided to use Java to ensure mobile compatibility and cross-device functionality.”

2. “How do you reverse a string in Java?”

This is a common interview question asked when organizations use Java extensively. There is no specific utility for reversing in Java, so this problem will showcase your problem-solving skills and your domain knowledge of Java. These kinds of “puzzle” questions are very common in coding interviews, and the specifics of each question will change depending on how much experience is required for the position and the coding languages used at the organization.

Attempting these kinds of questions will help you prepare for coding interviews. If you have difficulties finding an answer, searching for threads on StackOverflow can help. StackOverflow is a website focused on helping developers find answers to their technical questions — finding different iterations of how to reverse a string can help you understand the process.

3. “What are Loops in Java? When would you use each type of loop?”

Loops are a key function in Java that allow a program to repeat a statement, or set of statements. A question like this is common for more junior-level developer positions and gives you the opportunity to demonstrate your knowledge of the three main types of loops in Java.

For loops are used to repeatedly execute statements in a set way. These loops are used when the programmer knows how many times a set of instructions should be executed.

While loops are used to execute statements repeatedly until a condition is fulfilled. Before each execution, a condition is checked to see if the loop should continue running.

Do-while loops are similar to while loops, but the condition is checked after a statement or set of statements. As such, a do-while loop will run at least once, but a while loop might never loop if a condition is met before it can run.

An image highlighting the 3 main loops in Java.

4. “Which Java frameworks do you use and why?”

Java frameworks are an essential part of developing applications using the language. Frameworks are sets of pre-written code that can be used as a template for creating applications, allowing developers to program without writing the application entirely from scratch.

Your answer for this question depends entirely on your previous software development experience. If you are a more junior developer, you might not have used frameworks extensively in a professional capacity and that’s ok. One example of a popular Java framework that’s typically used to develop web applications is Spring.

Answering this question could look something like this: “Spring is my Java framework of choice. I enjoy using it because it’s lightweight, flexible and well-documented by the developer community. It took me some time to become familiar with the framework, but I’m confident the effort was worth it.”

5. “Code an application that does ‘x’.”

Many programming interviews involve actually writing code during the interview, either on a whiteboard or on a computer. There are many varieties of this question where the interviewer presents a problem or a set of functionalities that you’ll have to create on the fly. These can be a source of stress for many programmers, but it’s possible to prepare for these types of questions.

These coding task questions are varied, but some examples are seen more frequently than others. One such example is “FizzBuzz.” The FizzBuzz problem is typically a variation of the following: Write a Java program that prints out the numbers 1 to 50 but, for multiples of three, print the word “Fizz” and for multiples of five, print the word “Buzz.” For numbers that are multiples of both three and five, print the word “FizzBuzz.”

FizzBuzz is a classic programming question that’s focused on weeding out programmers who can’t actually code. The question is relatively basic, but interviewees without programming knowledge might not be able to write a program that can complete the task.

There are many possible programming problems that might be asked during the course of a programming interview. Whatever type of question you face, be sure to take the time to discuss your methodology as you work through a solution. Being able to come up with a solution and work through your thought process are both valuable skills for programmers.

Python interview questions

Python is a popular programming language used across a wide range of fields and applications. Many programming positions will require some knowledge of Python, so having a basic understanding of the language is vital for anyone looking to do well in an interview. This section will cover some possible questions to help you prepare.

If you don’t have prior experience and want to know more, check out our guide on learning Python. This guide covers why you should learn Python, the basics of the language and how to learn more.

1. “What is Python and what are the benefits of using it?”

Questions like this one can be used to showcase your level of knowledge and skill with a programming language and your understanding of situations where this language’s use is optimal.

Being prepared for this question can help you ace your programming interview. Python is one of the most easily accessible languages due to its use of “natural language” syntax, making it great for beginners and relatively easy for more experienced programmers to pick up. In addition, it can be used for a wide range of applications across many industries.

Some of Python’s benefits that you can incorporate into your answer include

Ease of use and debugging due to natural language syntax

Open source language status

Extensive library support

Robust developer and online community support

2. “What do you dislike about Python?”

This is an interesting question that can come up during the interview process. Knowing how to answer it requires a deep understanding of Python, its strengths and its weaknesses. It’s easier to research Python’s benefits and positive attributes without actually having a lot of experience in the language — knowing what you dislike about the language takes more experience.

A few drawbacks of Python include the following

Limited mobile application support

Interpreted nature can impact speed

Less memory-efficient than other languages

Answering this question could sound something like this: “Python is great for many applications, but there are always drawbacks to consider with any language. For example, Python is interpreted, which makes it easier to learn and use, but that aspect can impact efficiency. It might not be the best choice for an application where efficiency is the most important factor. Python’s limited mobile development support is another reason that can keep me from using it in some projects.”

3. “What are some of the most common mistakes that programmers make when using Python?”

This question gives interviewers the chance to see how a candidate stays organized and accurate when building software. Knowing how to avoid common mistakes is vital for any developer. Those mistakes include using tabs instead of spaces and using generic, non-unique identifiers. Another is neglecting to run regular code analyses — this can introduce typos or missing definitions for variables. Incorporate ways to avoid these mistakes into your answer to set yourself up for success.

4. “How do you identify bugs and issues in your code?”

Code is rarely, if ever, completely error-free, and knowing how to troubleshoot issues is a crucial skill for any programmer. Discuss any analysis tools you utilize, like PyChecker or Pylint, as well as any methodologies or strategies you use for debugging throughout your coding process. Answering this question could involve saying, “PyChecker is my debugging tool of choice. Writing clean, bug-free code is so important for developers, especially developers working on a team with others. Identifying and fixing bugs is an important part of my development process.”

5. “Code an application that does ‘x’.”

As we discussed in the Java section, you might have to use Python to code an example application using a prompt from the interviewer. When preparing for these types of questions, consider taking Python practice tests and working through your solutions out loud. The ability to describe your thought process as you code is crucial for these code-based questions.

Ready to ace your coding interview?

Programming is a great career, but getting started can be difficult without previous coding experience. If you’re looking for ways to build up your coding skills and ace programming interviews, enrolling in Berkeley Coding Boot Camp is a great place to start. You’ll learn in-demand coding skills from seasoned professionals while gaining hands-on experience working though real-world projects to populate your professional portfolio. Take the next step and enroll to start your programming career journey today!

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