C Interview Questions for Developers

Despite its age — it has been around since the 1970’s — C continues to be a popular first-time programming language and is used in a range of applications of every type, from game development to systems programming and embedded systems.

According to the CoderPad 2023 Developer survey, C is the 8th most in-demand language among technical recruiters and hiring managers.

We have developed practical coding tasks and interview questions tailored to evaluate developers’ C skills during coding interviews. Furthermore, we have compiled a set of best practices to ensure that your interview questions accurately gauge the candidates’ proficiency in C.

C example question

Help us design a parking lot

Hey candidate! Welcome to your interview. Boilerplate is provided. Feel free to change the code as you see fit. To run the code at any time, please hit the run button located in the top left corner.

Goals: Design a parking lot using object-oriented principles

Here are a few methods that you should be able to run:

• Tell us how many spots are remaining
• Tell us how many total spots are in the parking lot
• Tell us when the parking lot is full
• Tell us when the parking lot is empty
• Tell us when certain spots are full e.g. when all motorcycle spots are taken
• Tell us how many spots vans are taking up

Assumptions:

• The parking lot can hold motorcycles, cars and vans
• The parking lot has motorcycle spots, car spots and large spots
• A motorcycle can park in any spot
• A car can park in a single compact spot, or a regular spot
• A van can park, but it will take up 3 regular spots
• These are just a few assumptions. Feel free to ask your interviewer about more assumptions as needed

Best interview practices for C roles

To carry out successful C interviews, it is vital to consider various factors such as the candidate’s background and the specific engineering role. To ensure a fruitful interview experience, we recommend adopting the following best practices:

• Develop technical questions that reflect real-world business scenarios within your organization. This approach will effectively engage the candidate and assist in evaluating their compatibility with your team.
• Cultivate a cooperative environment by encouraging candidates to ask questions throughout the interview.
• As C is a low-level programming language, make sure your candidates have a grasp of low-level programming concepts like registers, memory addressing, and bitwise operations.

Moreover, adhering to established interview procedures is essential when conducting C interviews. This encompasses adjusting the complexity of the questions to match the candidates’ skills, promptly informing them about the status of their application, and providing them with the opportunity to ask about the evaluation process and collaboration with you and your team.