Top 20 Questions for C++ Developer Interview: Answers and Explanations

Introduction

When interviewing for a C++ developer position with three years of experience, it's important to be prepared for a variety of technical questions. In this article, we will discuss the top 20 questions that may be asked by an interviewer, along with detailed answers and explanations.

1. What is C++?

C++ is a general-purpose programming language that is an extension of the C programming language. It is widely used for developing software applications, system software, device drivers, and embedded systems.

2. What are the key features of C++?

C++ has several key features, including:

• Object-oriented programming
• Strong type checking
• Exception handling
• Templates
• Standard Template Library (STL)
• Multiple inheritance

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

C++ is an extension of the C programming language and includes additional features such as classes, objects, and inheritance. C++ also supports object-oriented programming, while C does not.

4. What is a class and an object in C++?

A class is a user-defined data type that contains data members and member functions. An object is an instance of a class. It represents a specific entity and can be used to access the data members and member functions of the class.

5. What is the difference between a structure and a class in C++?

In C++, a structure is similar to a class, but its members are public by default, while in a class, the members are private by default. Additionally, a class can have member functions, while a structure cannot.

6. What is inheritance in C++?

Inheritance is a feature of object-oriented programming that allows a class to inherit properties and behaviors from another class. It enables code reuse and the creation of hierarchical relationships between classes.

7. What are the access specifiers in C++?

C++ has three access specifiers:

• Public: Public members are accessible from anywhere.
• Private: Private members are only accessible within the class.
• Protected: Protected members are accessible within the class and its derived classes.

8. What is polymorphism in C++?

Polymorphism is a feature of object-oriented programming that allows objects of different classes to be treated as objects of a common base class. It enables code to be written that can work with objects of different types without needing to know their specific types.

9. What is a virtual function in C++?

A virtual function is a member function of a class that can be overridden by a derived class. It allows the derived class to provide its own implementation of the function while still maintaining the same interface.

10. What is a template in C++?

A template is a feature of C++ that allows for the creation of generic classes and functions. It enables the definition of a class or function without specifying the types of its arguments or return values. The types are determined when the template is used.

11. What is the difference between a template class and a template function?

A template class is a class that is parameterized by one or more types. It can be used to create objects of different types. A template function, on the other hand, is a function that is parameterized by one or more types. It can be used to perform operations on different types of data.

12. What is the difference between pass by value and pass by reference?

Pass by value involves making a copy of the value being passed to a function, while pass by reference involves passing the memory address of the value. Pass by value is used when the function does not need to modify the original value, while pass by reference is used when the function needs to modify the original value.

13. What is the difference between an array and a vector in C++?

An array is a fixed-size collection of elements of the same type, while a vector is a dynamic-size collection of elements of the same type. Vectors can grow or shrink in size as elements are added or removed.

14. What is the difference between a pointer and a reference in C++?

A pointer is a variable that stores the memory address of another variable, while a reference is an alias for another variable. Pointers can be reassigned to point to different variables, while references cannot be changed once they are initialized.

15. What is the difference between stack and heap memory?

Stack memory is used for local variables and function calls, while heap memory is used for dynamically allocated memory. Stack memory is automatically managed by the compiler, while heap memory must be manually allocated and deallocated.

16. What is the difference between new and malloc in C++?

The new operator is used to dynamically allocate memory for an object and calls the object's constructor, while the malloc function is used to dynamically allocate memory and does not call the object's constructor. The delete operator is used to deallocate memory allocated with new, while the free function is used to deallocate memory allocated with malloc.

17. What is a smart pointer in C++?

A smart pointer is a class template that provides automatic memory management for dynamically allocated objects. It automatically deallocates the memory when it is no longer needed, preventing memory leaks.

18. What is exception handling in C++?

Exception handling is a mechanism in C++ that allows for the handling of runtime errors and abnormal conditions. It involves the use of try, catch, and throw statements to catch and handle exceptions.

19. What is the difference between static and dynamic binding in C++?

Static binding, also known as early binding, occurs when the function call is resolved at compile-time based on the static type of the object. Dynamic binding, also known as late binding, occurs when the function call is resolved at runtime based on the dynamic type of the object.

20. What are the advantages of using C++ over other programming languages?

Some advantages of using C++ over other programming languages include:

• Efficiency and performance
• Ability to directly manipulate memory
• Support for object-oriented programming
• Extensive libraries and frameworks
• Wide range of application domains

Conclusion

Preparing for a C++ developer interview with three years of experience requires a solid understanding of the language and its key concepts. By familiarizing yourself with the top 20 questions and their answers provided in this article, you will be better equipped to showcase your knowledge and skills during the interview process.