Digitalogy logo

Top C++ Interview Questions and Answers for 2024 (Updated)

c++ interview questions and answers

In this article, we have highlighted the top C++ interview questions and answers of 2024 at different levels of the professional environment. 

If you are an aspiring C++ developer and wish to know about what interview rounds can be like, you have come to the right place. The interview process for C++ programming questions can be very hectic and difficult as well. Even if you hold a great deal of knowledge in a C++ Programming Language, there is a possibility that you might get confused if asked questions in that field during the interview. 

In this blog, you will find the C++ interview questions an interviewer can ask you in rounds of interviews to check your knowledge and skills. Before looking at the questions, let’s understand the basics of  C++ in detail. 

What is C++? 

Object-oriented programming language C++, which belongs to the “C” family of languages, was created by prominent computer scientist Bjorne Stroustrop. To give programs more granular control across memory and system resources, it was created as a cross-platform enhancement to “C”. 

The programming language that all coders must know and love is C++. It remains as current as it was during the middle of the 1980s. It is generally routinely utilized when coding because it is a general-purpose, goal-oriented programming language.

As a result, some positions require candidates to be proficient in C++. Top IT businesses like Evernote, LinkedIn, Microsoft, Opera, NASA, and Meta all use it due to its reliability, efficiency, and variety of possible configurations.

This is why, you must thoroughly prepare for such top C++ programming interview questions to impress hiring managers and land a job. 

Advantages of using C++ Programming Language

  • Object-Oriented: Since C++ Programming Language is an object-oriented programming language, entities and the changes that take place close to them are the central objective. Contrary to conventional or hierarchical programming, which calls for a number of operational steps to be completed, this allows it much simpler to alter code.
  • Speed: The best choice is C programming language when efficiency is a top priority. Compared to other general-purpose programming languages, C++ programs generate and execute much faster.
  • Rich Library Support: The C++ Standard Template Library (STL) has a number of features that can help you write code very quickly. For instance, STLs are available for a variety of categories, such as collections, hash tables, and maps.

Top C++ Viva Questions and Answers for Beginners 

Q1. What is Class? 

Ans. A user-defined data type is known as a class. Declaring a class entails using the word class. The class’s three modifiers- private, public, and protected control which users and data members have access to the class’s data. The class defines the category of items’ type declaration. It establishes a type of data instead of the data itself and establishes the structure of the data.

Q2. What are the advantages of using C++?

Ans. – Since C++ is a very flexible programming language, programs developed in it ought to run on practically any platform.

Classes, objects, inheritance, polymorphism, and abstraction are all features of the C++ programming language.

-C++ has an inheritance concept. With inheritance, superfluous code can be removed while preserving existing classes.

Q3. What is Data Binding and Abstraction? 

Ans. Data binding is a technique for creating a connection between the information displayed by an app and its UI. The elements that are linked to it rapidly respond to changes in the data anytime they occur if the binding has the proper settings and the data offers new communication.

Data abstraction is the method of condensing a vast amount of information into a straightforward depiction of the entire. Abstraction is the method of reducing something to a collection of fundamental features by removing or removing attributes.

Q4. How can you specify a class in C++? 

Ans. When defining a class in C++, you must use the phrase class and identity (class name). The class core description is encapsulated in curly brackets. The sentence comes to a close with a semicolon.

For example,

class name{

// some data

// some functions

};

Q5. Differentiate between C and C++.

Ans. 

C Programming language focuses on procedures. C++ Programming language focuses on object-orientation.
Data handling is not supported. To ensure that data structures and procedures are employed properly, encapsulation conceals data.
In C, stacking of operators and procedures is not permitted.In C++, stacking of operators and procedures is allowed.
Common Differences Between C and C++
Here are some other C++ Interview Questions & Answers for Freshers

Read our other Interview-related articles:

Top C++ Interview Questions and Answers for Intermediates 

Q6. Explain constructor in C++.

Ans. The member function Object() [native code] is called instantly when an object is created. Constructors are given the same identity as the class to which they correspond. Thus the compiler interprets the member function as a function called Object() that is written in { [native code] }. Additionally, return types are absent from constructors.

For example: 

class A{
 private:
  int val;
 public:
  A(int x){             //one argument constructor
   val=x;
  }
  A(){                    //zero argument constructor
  }
}
int main(){
 A a(3);     
 return 0;
}

Q7. What is a Virtual Function in C++? 

Ans. A virtual function is employed to take the place of the core class’s implementations. The replacement has consistently been performed when an object belongs to a derived class, regardless of whether it is accessed using a base pointer or a dependent pointer.

The base class procedure is specified with the keyword virtual whenever the same procedure term is used in both the core and extended classes.

The kind of item that the base class pointer references when a procedure is designated virtualized influences which function C++ will call at execution. We can launch multiple instances of the virtual functions by changing the base class reference to correspond to different objects.

Q8. What is a class template in C++? 

Ans. A class template outlines the process for creating classes from variables. Class templates are generally used to construct containers. A class template is constructed by giving it a collection of kinds as template inputs.

Q9. What do you understand about “call by value” and “call by reference” in C++? 

Ans. Call by value: When calling by value, we send a duplicate copy of the variable to the functions. These duplicated variables have a new memory allocated to them; therefore any modifications to such values have no impact on the variable used in the primary function.

Call by reference: We give the call by reference method the variable’s address, and it uses that location to find the actual argument that was used to execute the function. Changes to the variable hence affect the passing argument.

Q10. What is the difference between operator overloading and functioning overloading in C++ Programming? 

Ans. Operator overloading is the practice of redefining a standard operator such that it has a different meaning when used with instances of a class.

Function overloading is the possibility of many variations of a single function. A function’s identity changes, suggesting that each repetition of the procedure utilizes a distinct set of parameters.

Top C++ Questions and Answers for Experts 

Q11. What is Inheritance in C++? 

Ans. The process of generating different classes, usually referred to as derived classes, from preexisting classes is known as inheritance. The already existing classes are referred to as base classes. Derived classes can add their functionality and improvements while still inheriting every one of the base class’s abilities.

The derived class inherits some properties with the base class even the derived class can have some additional properties of its own. For example

class Animal{
    // walk() function
    // eat() function
};

class Dog : public Animal{
    // bark() function
};

Q12. What do you understand by overloading? 

Ans. Overloading is the term used to describe when one object exhibits many behaviors. Two things can have a similar name, yet they can perform different tasks.

The same function name or operator can have numerous definitions defined within the same context in C++. Function overflowing and overloading are synonyms for each other in this context.

Code for Function Overloading:-

#include <iostream>
using namespace std;

// Function to add two integers
int add(int a, int b) {
    return a + b;
}
// Function to add two doubles
double add(double a, double b) {
    return a + b;
}
int main() {
    int num1 = 5, num2 = 10;
    double num3 = 2.5, num4 = 3.7;
    
    // Call the integer version of the add function
    int ans1 = add(num1, num2);
    std::cout << "Sum of integers = " << ans1 << std::endl;
    
    // Call the double version of the add function
    double ans2 = add(num3, num4);
    std::cout << "Sum of doubles = " << ans2 << std::endl;
    
    return 0;
}

Output:

Sum of integers = 15
Sum of doubles = 6.2

Q13. What is Multithreading in C++ Language? 

Ans. Your device’s capacity to run several or maybe more programs at once is known as multitasking. A more complex variation of multitasking is multithreading. A multithreaded program consists of two or maybe more simultaneous-running elements. A thread is a part of such a program, but every thread provides a unique execution flow.

Q14. Elaborate on what is upcasting in C++ Programming.

Ans. Upcasting is the method of changing a source or reference to something like a base class from a derived class. To rephrase it in another way, by upcasting a derivative type, one can think of it as if it were its basic type. Anytime there isn’t a typecast applied explicitly, open inheritance has always been permitted.

Q15. What is the Local and Global scope of a variable? 

Ans. Global variables are helpful for information that is largely consistent or that needs to be accessible by several scripting methods, like a session id. A local variable, in contrast, has a constrained range because it only lives in the section in which it has been created. Once that step is finished, the variable is deleted, and its values are gone.

Read our other Interview-related articles:

Conclusion 

After going through these C++ interviews and viva questions and answers, you must have gained some understanding of some crucial C++ Programming languages. These C++ programming questions are a few questions that can be very useful during the C++ interview process. 

We would suggest you be prepared well before having your C++ interview rounds. An interview can only be done well when you have all the knowledge of a particular topic. C++ is a very wide field, so having a great knowledge of the field is very important. 

FAQs 

Q1. Is C++ a good programming language for a career?

Ans. Yes. C++, one of the most popular languages, has great demand which will eventually increase, so you should definitely learn C++. 

Q2. What are the libraries in C++? 

Ans. Diagnostics Library, General Utilities Library, Standard String Templates, Localization Classes and Templates, The Containers, Iterators, and Algorithms Libraries, The Standard Numerics Library, The Standard Input/Output Library.

Q3. What positions am I eligible for with C++ programming skills?

Ans. Programmer, Software Developer, Quality Analyst, Software Developer, C++ Analyst, and Programming Architect are a few choices that you can opt for after learning C++. 

Claire D. Costa

Claire D. Costa

Experienced technical content writer, skilled at simplifying complex topics for broad audiences. Passionate about crafting engaging narratives and fostering effective communication.

Want to hire
Remote Developers?

Elevate Your Business: Tap into Global Talent, Boost Efficiency, and Cut Costs with Remote Developers. Unlock Success Now!