C++ Developer Interview Questions

Responsibilities

 C++ developer responsibilities may include:

• Designing reliable C++ code
• Developing new software
• Communicating with other developers to develop an application
• Building database systems
• Performing cross-functional implementation and tests

Skills

C++ is the basis of many applications. In order to utilize their knowledge to provide the best code possible, skilled C++ developers will:

• Communicate effectively with other engineers in their team
• Possess an eye for detail to identify errors in code
• Utilize creative thinking to automate processes
• Utilize customer feedback to fix faulty code
• Maintain a solid work ethic to provide the best product possible

Qualifications

Many entry-level positions require applicants to possess a bachelor’s degree in computer science or a related field. However, it is not uncommon to find self-taught developers with little-to-no formal education. There are many courses and certifications outside of formal education that candidates can utilize to make themselves more attractive to employers. 

If you’re getting ready to interview for a position as a C++ developer, you can prepare by researching the company as much as possible. Learn about the 9 things you should research before an interview.

Salary

Salaries for C++ developers range between $70K and $96K with the median being $84K. 

Factors impacting the salary you receive as an C++ developer include:

• Degrees (associate's or equivalent technical training, bachelor's, master's)
• Years of Experience
• Location
• Reporting Structure (seniority of the manager you report to, number of direct reports)
• Level of Performance - exceeding expectations

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C++ Developer Interview Questions

Question: Can you describe what the basic structure of a C++ program is?

Explanation: As a C++ developer, you can anticipate that the majority of your interview will involve technical questions. This is an example of what a technical question looks like. The best way to answer technical questions is with a straightforward and concise manner.

Example: “The basic structure every C++ program will have is a preprocessor directive with a main function declaration followed by a block of code and then a returning point to the main function which indicates successful execution of the program. The content, commands, and information in each of these sections can vary greatly, but the basic structure remains the same.”

Question: What is the purpose of comments in C++?

Explanation: This is another technical question. Technical questions typically deal with definitions of terms or information used in the job for which you are interviewing. You can define the term and then provide an example of how it is used.

Example: "A comment in C++ is source code which is ignored by the compiler. The programmer uses comments to add a description or additional information about their source code. There are two ways to add comments in C++. These include a single line comment denoted by // and a block comment which is indicated by /*.”

Question: What is the difference between a declaration and definition of a variable used in C++?

Explanation: Some technical questions will ask you to compare two different terms. The interviewer is attempting to discover the depth of your skills and knowledge in this field. You may want to define each term and then state their differences or how they are used.

Example: “A declaration of a variable is used to specify the data type of a variable and the variable name. This tells the compiler to reserve the space for a variable in the memory according to the data type specified. A definition is the implementation of the declared variable which ties up an appropriate value to the declared variable so the linker associates reference to the appropriate entities.”

Question: Can you discuss the difference between a local and global scope of a variable?

Explanation: Again, the interviewer is asking you to compare two different terms used by C++ developers. This technical question is structured a little differently than the previous ones. When on an interview, make sure you listen carefully to the interviewer’s questions and respond to them appropriately.

Example: “There are two types of scope in C++, local and global. A variable has a local scope when it is declared inside a code block. The variable remains active only inside the block and is not accessible outside the code block. Conversely, a variable has a global scope when it is accessible by the entire program. A global variable needs to be declared at the top of a program before all the function definitions.”

Question: When there is a global and a local variable in the program with the same names, which one takes precedence?

Explanation: This is a follow-up question to the previous one. Interviewers will often ask follow-up questions if they are looking for additional information or the topic they are asking about is important to them. You should always be prepared for follow-up questions during an interview.

Example: “When a local variable has the same name as that of a global variable, the compiler will always give precedence to the local variable. Programmers can still use variables with the same names, but you need to keep this rule in mind. Sometimes it is easier to amend the variables’ names to simplify this issue.”

Question: What is a constant in the context of a C++ program? Can you describe the different types of constants?

Explanation: In this technical question, the interviewer is specifically asking you to define the concept and then provide an example. When the interviewer asks this type of question, make sure you follow their directions precisely. In addition to determining your knowledge in this area, they are also testing to see how well you follow directions.

Example: “In the context of a C++ program, a constant is a type of expression that has a fixed value. Constants can be divided into integer, decimal, floating-point, character, or string, depending on the type of data. C++ also supports octal and hexadecimal constants.”

Question: As a programmer, how do you define and then declare constants in C++?

Explanation: This technical question combines elements of several of the questions you already been asked. As the interview progresses, the interviewer will ask these types of compound questions. They’re digging deeper into your technical knowledge and ensuring you know how to use the programming elements you’ve already discussed.

Example: “In C++, you define constants using the #define preprocessor directive. Once you’ve defined a constant, you can use it throughout the program and substitute its value. You declare constants in C++ using the “const” keyword. This is similar to declaring a variable but with a constant prefix. Whenever the type of a constant is not specified, C++ compiler defaults to an integer type.”

Question: Can you comment on the function of an assignment operator in C++?

Explanation: This is yet another technical question, and this one asks you to comment on a particular element of C++ programming.  Although the format is different, the purpose is the same in that it wants you to define a term and then possibly provide an example of how it is used.

Example: "An assignment operator in C++ is a command used to assign a value to another variable. Two ports of the assignment operator are lvalue (left value) and rvalue (right value). The left value will always be a variable, whereas the right value can be a constant, a variable, the result of an operation, or any combination of these. The assignment operation always takes place starting from the right and then moving to the left and never in the opposite direction.”

Question: Can you describe what the arithmetic operators are in C++?

Explanation: This technical question asks you to describe specific functions used within C++ programming. To prepare for an interview, you should research the job posting as well as the company with which you are interviewing. This will help you narrow down the types of questions you can anticipate being asked so you can prepare your answers.

Example: “C++ supports all of the basic arithmetic operators, including addition, subtraction, multiplication, division, and percentage. These operators are the same as actual arithmetic operations.”

Question: Can you explain the difference between a while and a do-while loop and describe how they are used?

Explanation: The interviewer is asking you one more technical question. When preparing for an interview, you should practice these questions out loud. First, ask yourself the question or have somebody else do it, then answer the question out loud. This helps you develop muscle memory around the answer and practice how you will state your response.

Example: “A while loop is a command which is executed as long as the condition in the given expression is true. In a while loop, the terminating condition is at the beginning of the loop, and once it is fulfilled, no further iterations of the loop are executed. In a do-while loop, the statement inside the loop is executed at least once. This is because the loop condition is at the end. These are the main differences between the while and do-while loops.