Essential C++ Interview Questions and Example Answers

By Indeed Editorial Team

Updated 22 September 2022

Published 6 June 2021

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

Given that C++ is an object-oriented programming language with widespread general use, many jobs require candidates to have a solid knowledge of programming in C++. When preparing for a C++ related job interview, it will help to review the questions that the interviewers are most likely to ask. This will let you assess your current knowledge level and polish your C++ programming skills further.

In this article, we will look at some of the most-asked C++ interview questions and review the answers to some of these.

General C++ Interview Questions For Developers

You may encounter the following general interview questions when you go for a C++ developer job interview:

  1. Give me a definition of C++.

  2. What do you like the most about programming with C++?

  3. What are some of the top projects you have done with C++?

  4. In your opinion, what specific skills should a C++ developer have?

  5. What are your strong points in programming in C++?

  6. What are your weaknesses in programming in C++?

  7. What do you do to keep up with C++ news and trends?

  8. What made you apply for a C++ developer position in our company?

  9. What were your specific job responsibilities in your previous position as a C++ developer?

Related: How to Prepare for a Job Interview

Interview Questions About C++ Programming Experience And Background

The interviewers are likely to ask the following questions about your C++ programming experience and background:

  1. Why would you call C++ an object-oriented programming language?

  2. What is the difference between C and C++?

  3. In C++, what is the concept of inheritance? Please explain.

  4. What do you know about abstraction in C++?

  5. What is a namespace in C++?

  6. What is a class template in C++?

  7. How would you initiate the variable C in C++? Mention the different ways.

  8. Explain an inline function and give its syntax in C++.

  9. What do you know about encapsulation in C++?

  10. What do you know about storage class in C++? List some storage class names.

Related: 9 Common Mistakes to Avoid in an Interview

In-Depth C++ Programming Interview Questions

Here are some in-depth C++ programming interview questions to practice before the interview:

  1. How will you use volatile keywords in C++?

  2. What do you know about vTable and vptr in C++? How does the C++ compiler maintain and use them?

  3. In C++, what is the difference between function and operator overloading?

  4. What is the main difference between the keyword struct and class?

  5. Talk about the differences between Java and C++.

  6. What do you understand by Abstract class in C++?

Related: 23 Interview Tips: How to Get the Job

Commonly Asked C++ Interview Questions And Sample Answers

You can refer to the following C++ interview questions and sample answers to prepare for a C++ developer job interview:

1. What do you understand by access modifiers in C++?

This is a question that you might frequently encounter when interviewing for a C++ developer position. You can explain what access modifiers are and their use in C++ programming. You can also mention the different types of access modifiers.

Example: "Data hiding involves restricting access to data members of a class to prevent other functions and classes from data tampering. At the same time, you will want to provide access to some functions and data. The three types of access modifiers are public, private and protected access modifiers. You can use the public access modifier to create public data and functions and access them from anywhere in the program.

For creating private data and functions that only private members from within the class can access, use the private access modifier. The protected access modifier creates protected data and functions that are accessible from the class and the derived class."

2. What are some of the advantages of programming in C++?

Interviewers often ask this question to test your understanding of the various benefits of C++ programming. You can mention the different C++ features that aid programmers.

Example: "C++ offers many programming advantages. To begin with, it is portable and not platform-dependent. You can write a program in C++ and successfully run it on both Linux and Windows operating systems. As it is an object-oriented programming language, you can reuse the code, use data as an object to tackle real-world issues and use single or many statements for multiple purposes. C++ allows you to manage and control memory using dynamic memory allocation pointers. You can scale a C++ program by small and large data and build resource-intensive applications. It allows data hiding, enabling programmers to build more secure programs. Then it is compatible with the C programming language. There are many online courses, lectures, articles and forums about C++, offering plenty of learning resources and programming support."

3. Explain the differences between reference and pointer in C++.

The interviewer may ask this question to gauge how well you can understand and explain technical concepts.

Example: "There are several differences between a reference and a pointer. In C++, a reference is another name for an existing variable and a pointer is a variable holding the memory address of another variable. Another difference is that after you have assigned a reference variable, you cannot reassign it with different address values. You can do so with a pointer variable since it is independent. Also, you cannot assign a null value to a reference variable, but you can do so to a pointer variable. Additionally, at the time of declaration, you need to initialise a reference variable. This is not necessary with a pointer variable."

4. List the Object-Oriented Programming concepts in C++.

Interviewers ask this question to find out how much you know about object-oriented programming in C++ and its basic concepts.

Example: "The basic OOP concepts are classes and objects, encapsulation, abstraction, inheritance and polymorphism. When you want to specify data structure and define a data type, you use classes. And you can use classes to create objects. Encapsulation, which is also called data hiding, uses private, public and protected access specifiers to combine data and the associated operations.

With abstraction, you can use interfaces and abstract classes to show only the necessary details of internal implementations. With inheritance, you can transfer the property of one class to another. Polymorphism is letting one class inherit attributes and methods from another class."

5. Explain the difference between an array and a list in C++.

By asking this question, the interviewer will want to gauge your knowledge of data types. You can explain what arrays and lists are and provide a few differences.

Example: "Arrays are sequence containers of a fixed size that are in a linear sequence and have a specific number of elements, while lists are generally elements that are not of a fixed size and which are linked together with pointers. Both arrays and lists are used for data storage, but arrays can contain only elements of the same data type and lists can contain elements of different data types."

6. What is a DLL? How would you export a function from a DLL?

The interviewer may ask this question to find out what you know about DLL (Dynamic Link Library).

Example: "DLLs are executable files that contain a library of functions and other informative resources that are accessible for a program for use with different applications. By using DLL, you can promote code reuse and reduce memory and disk space usage. To export functions from a DLL, you can create and use a modular definition file. You can also use the _declspec(dllexport) keyword."

7. What is a friend function? List its characteristics.

This question can help the interviewer understand if you know how to generate efficient code when programming with C++.

Example: "A friend function of a class is a function that allows access to the private and protected data of that class. To get access, it is necessary to use the keyword friend inside the body of the class to declare the friend function. The characteristics of a friend function are that the function is outside the scope of the class of which it was declared a friend, you cannot call it using the object since it is outside the class scope and you must, instead, call it like a normal function without the object."

8. Define a destructor in C++. What are its rules?

This interview question tests your knowledge of the destructor function and its rules.

Example: "A destructor is a member function in a class that is automatically invoked when the object is deleted or passes out of scope. It deallocates the memory of the object. According to destructor rules, the destructor name should be the same as the class name and there can only be one destructor in a class. You should also begin the destructor declaration with a tilde symbol. Destructors do not allow parameters or have return types. If you do not specify a destructor in your code, the compiler will insert the default one."


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