C++ Developer Interview Questions
In the realm of software development, C++ continues to be a fundamental programming language, underpinning many systems and applications due to its efficiency. As enterprises seek to hire proficient C++ developers, pinpointing the right criteria for evaluation is imperative. This article provides a comprehensive set of 25 questions designed to assess a candidate's depth of knowledge and expertise in C++. By leveraging this guide, organizations can enhance their recruitment process and ensure the selection of well-qualified C++ developers.
Explain the difference between C and C++.
Answer: C++ is an extension of C with additional features like classes, objects, and other object-oriented features.
What is polymorphism in C++?
Answer: Polymorphism allows a single function or method to work on different types or classes, supporting both compile-time (overloading) and runtime (overriding) behaviors.
How is memory management handled in C++?
Answer: C++ provides manual memory management using `new` to allocate and `delete` to deallocate memory.
What are smart pointers?
Answer: Smart pointers manage the memory of objects, ensuring objects are deleted automatically when not in use. Examples include `unique_ptr`, `shared_ptr`, and `weak_ptr`.
Describe the Rule of Three.
Answer: It states that if a class defines one of the following (destructor, copy constructor, copy assignment operator), it should probably define all three.
What is the difference between a class and a struct in C++?
Answer: By default, members of a struct are public, while members of a class are private.
Explain function overloading.
Answer: Function overloading allows multiple functions in the same scope to have the same name but different parameters.
What is the role of a destructor?
Answer: A destructor is called when an object goes out of scope to release any resources allocated to it.
Describe templates in C++.
Answer: Templates allow functions and classes to operate on generic types, promoting code reuse.
What is RAII?
Answer: Resource Acquisition Is Initialization ensures resources are acquired and released in the same scope, typically using object lifetime.
What is the difference between the stack and the heap?
Answer: Stack is used for static memory allocation (local variables), while heap is used for dynamic memory allocation (`new` and `delete`).
How do you handle exceptions in C++?
Answer: Using the `try`, `catch`, and `throw` constructs.
Explain the concept of move semantics.
Answer: Move semantics allow resources of a temporary object to be moved rather than copied, optimizing performance.
What is the Standard Template Library (STL)?
Answer: STL is a library of template classes and functions in C++ that provides common data structures and algorithms.
Describe the differences between `public`, `protected`, and `private` in C++.
Answer: `public` members are accessible from any function; `protected` members are accessible from member functions of the same class and its descendants; `private` members are only accessible from member functions of the same class.
What are lambda functions?
Answer: Lambdas are anonymous functions or function objects useful for short scope operations.
How does `virtual` keyword work in C++?
Answer: The `virtual` keyword is used to allow functions to be overridden in derived classes.
What is a namespace in C++?
Answer: Namespaces prevent naming collisions by introducing a named scope.
Explain the use of the `volatile` keyword.
Answer: `volatile` tells the compiler that a variable can change externally, preventing certain optimizations.
What are iterators?
Answer: Iterators are objects that point to elements in a container and can traverse through them.
How is `new` different from `malloc`?
Answer: `new` calls the constructor and returns the proper type, while `malloc` allocates raw memory without initialization.
Describe the role of `const` keyword.
Answer: `const` declares a variable as constant, meaning its value cannot be changed.
What is a copy constructor?
Answer: A copy constructor defines how an object should be copied when passed as a value.
What is a virtual destructor?
Answer: A virtual destructor ensures the correct derived class destructor is called when an object is deleted through a pointer to the base class.
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