Top 30 Most Common c++ basic interview questions You Should Prepare For

Landing a job as a C++ developer often hinges on how well you can articulate your understanding of fundamental concepts. Mastering c++ basic interview questions can significantly boost your confidence, providing clarity and improving your overall interview performance. Preparation is key, and knowing what to expect is half the battle. By familiarizing yourself with these frequently asked questions, you'll be better equipped to impress your interviewer and demonstrate your proficiency in C++.

What are c++ basic interview questions?

c++ basic interview questions are designed to assess a candidate's foundational knowledge of the C++ programming language. These questions typically cover areas like data types, object-oriented programming principles, memory management, and basic syntax. They are essential for evaluating a candidate's ability to write clean, efficient, and reliable C++ code. The purpose of these questions is to ensure that candidates possess a solid understanding of the core concepts necessary to build more complex applications. Mastering these c++ basic interview questions ensures that you can confidently discuss core concepts and showcase that you have a solid understanding of C++.

Why do interviewers ask c++ basic interview questions?

Interviewers ask c++ basic interview questions to gauge a candidate's fundamental understanding of the language. They want to determine if you have a strong grasp of the core concepts and principles that underpin C++ programming. This includes your ability to explain object-oriented programming concepts like inheritance and polymorphism, as well as your knowledge of data structures, memory management, and other essential topics. By asking these questions, interviewers are assessing not only your technical knowledge but also your problem-solving ability and how well you can apply theoretical concepts to practical situations. Strong performance on these c++ basic interview questions demonstrates you have a solid foundation to build upon and can handle more complex tasks.

Preview of the 30 c++ basic interview questions:

• 1. What is C++?

• 2. What are the different data types present in C++?

• 3. What is std in C++?

• 4. What is the difference between C and C++?

• 5. Explain inheritance in C++.

• 6. What are static members and static member functions?

• 7. What is operator overloading?

• 8. Which operators cannot be overloaded in C++?

• 9. What is an abstract class?

• 10. What is the difference between class and struct?

• 11. Explain the concept of polymorphism in C++.

• 12. What is a virtual function?

• 13. What is the size of void in C++?

• 14. What is the difference between pointers and references?

• 15. What is call by value and call by reference?

• 16. Explain encapsulation in C++.

• 17. What are constructors and destructors?

• 18. Explain the difference between shallow copy and deep copy.

• 19. What are templates in C++?

• 20. What is a namespace?

• 21. What is the use of the const keyword?

• 22. What is the difference between stack and heap memory?

• 23. What is a pure virtual function?

• 24. What is the meaning of inline function?

• 25. What is the difference between new and malloc?

• 26. How does exception handling work in C++?

• 27. What is function overloading?

• 28. What is the difference between overloading and overriding?

• 29. What are smart pointers?

• 30. What is the output of this program snippet?

## 1. What is C++?

Why you might get asked this:

This question tests your fundamental understanding of the language. Interviewers want to see if you can clearly define C++ and highlight its key features. It’s a foundational question for assessing your overall knowledge of c++ basic interview questions topics.

How to answer:

Begin by defining C++ as a general-purpose programming language. Then, mention that it's an extension of C that supports multiple programming paradigms, including object-oriented, procedural, and generic programming. Highlight features like classes, inheritance, polymorphism, and templates.

Example answer:

"C++ is a powerful, general-purpose programming language. It evolved from C and added object-oriented features, allowing us to create reusable and modular code through classes and inheritance. For example, I once used C++ to build a system where inheritance drastically simplified the management of different types of hardware components. So, in a nutshell, C++ combines the low-level control of C with high-level object-oriented design."

## 2. What are the different data types present in C++?

Why you might get asked this:

This question assesses your knowledge of fundamental data types in C++. It's a basic building block for understanding how variables and data are handled in the language, which is critical when addressing c++ basic interview questions.

How to answer:

Start by listing the basic data types: int, char, float, double, bool, and void. Then, mention derived data types such as arrays, pointers, references, and structures (struct). Briefly explain the purpose of each type.

Example answer:

"C++ has several core data types. The basic ones include int for integers, char for characters, float and double for floating-point numbers, bool for boolean values, and void representing the absence of type. Then we have derived types like arrays, pointers which store memory addresses, references which are aliases, and structures, which group variables. I recall a project where I used structures to efficiently manage complex data records, and the choice of appropriate data types was critical for performance, so you see how important that is to understand."

## 3. What is std in C++?

Why you might get asked this:

This question checks your understanding of namespaces in C++ and how to use the standard library. It's relevant because the standard namespace is fundamental to most C++ programs. Addressing c++ basic interview questions involves understanding how standard components are organized.

How to answer:

Explain that std is the standard namespace in C++ that contains the C++ Standard Library's functionality. Mention that it includes commonly used components like cout, cin, vector, and algorithms, and its purpose is to avoid name conflicts.

Example answer:

"std is the standard namespace in C++. It essentially organizes the C++ Standard Library, and it prevents naming conflicts when we use common elements like cout, cin, or vector. I've seen firsthand how using namespaces makes codebases more manageable, particularly in larger projects, ensuring that our naming conventions don't clash with external libraries. Understanding namespaces is pretty fundamental for any C++ developer, I think."

## 4. What is the difference between C and C++?

Why you might get asked this:

This question explores your understanding of the evolution and core differences between C and C++. Interviewers want to see if you know C++'s object-oriented capabilities. Many c++ basic interview questions address the differences with its C predecessor.

How to answer:

Explain that C is a procedural programming language, while C++ supports both procedural and object-oriented programming. Highlight C++'s features like classes, inheritance, and polymorphism, which are not available in C.

Example answer:

"The main difference lies in their programming paradigms. C is primarily a procedural language, meaning it focuses on functions and step-by-step execution. C++, on the other hand, supports both procedural and object-oriented approaches. It introduces key object-oriented concepts like classes, inheritance, and polymorphism, which C lacks. I've used C++ in projects where object-oriented design greatly improved code maintainability and scalability compared to when I've used C. So, the key takeaway is that C++ builds upon C by adding object-oriented capabilities."

## 5. Explain inheritance in C++.

Why you might get asked this:

This question tests your understanding of object-oriented programming principles. Inheritance is a crucial concept for code reuse and creating hierarchical class structures. This is one of the core c++ basic interview questions.

How to answer:

Explain that inheritance allows a class (derived class) to acquire properties and behavior (methods) from another class (base class). Emphasize that it promotes code reuse and hierarchical classification.

Example answer:

"Inheritance is a fundamental object-oriented feature that allows a class to inherit properties and methods from another class. The inheriting class is called the derived class, and the class it inherits from is the base class. This allows us to reuse code and create hierarchical relationships between classes. In a project where I modeled different types of vehicles, inheritance allowed me to create a base 'Vehicle' class and then derive specific classes like 'Car' and 'Truck,' inheriting common properties and behaviors. Inheritance promotes code reusability and helps us organize code more effectively."

## 6. What are static members and static member functions?

Why you might get asked this:

This question assesses your knowledge of static members and functions, which are important for managing class-level data and behavior. Interviewers want to know if you understand when and how to use them. Understanding static members is an important part of mastering c++ basic interview questions.

How to answer:

Explain that static members belong to the class rather than to any object instance, meaning all instances share the same static member. Also, explain that static member functions can access only static data members or other static member functions.

Example answer:

"Static members belong to the class itself, not to individual instances. This means that all objects of the class share the same static member. Static member functions can only access static members of the class and are called using the class name rather than an object. I once used a static member to keep track of the number of instances created for a particular class. This allowed me to monitor resource usage effectively without needing to track it in each object instance. Static members are handy for class-level data that's shared across all instances."

## 7. What is operator overloading?

Why you might get asked this:

This question checks your understanding of operator overloading, which allows you to define custom behavior for operators when applied to class objects. It's a more advanced topic within c++ basic interview questions.

How to answer:

Explain that operator overloading allows C++ operators to have user-defined meanings when applied to class objects, enabling intuitive syntax for operations like + or * on user-defined types.

Example answer:

"Operator overloading lets you redefine how standard operators like +, -, *, and / work with user-defined types like classes. This allows us to use these operators in a more intuitive way with our own objects. For instance, I overloaded the + operator for a Vector class so that it would add the components of two vectors together. This makes the code much cleaner and easier to read than if I had to write a separate function to perform vector addition. Operator overloading, when used judiciously, can enhance code readability and maintainability."

## 8. Which operators cannot be overloaded in C++?

Why you might get asked this:

This question tests your knowledge of the limitations of operator overloading in C++. Interviewers want to see if you understand which operators have fixed meanings. Demonstrating this knowledge in c++ basic interview questions shows a deeper understanding of the language.

How to answer:

Mention that the scope resolution operator ::, sizeof, member access ., pointer-to-member .*, and ternary conditional ?: operators cannot be overloaded.

Example answer:

"There are a few operators in C++ that you can't overload. These include the scope resolution operator ::, the sizeof operator, the member access operator ., the pointer-to-member operator .*, and the ternary conditional operator ?:. These operators are fundamental to the language's syntax and behavior, and overloading them could lead to ambiguity or break core functionality. Knowing which operators cannot be overloaded is important for avoiding unexpected behavior in your code."

## 9. What is an abstract class?

Why you might get asked this:

This question assesses your understanding of abstract classes and pure virtual functions, which are important for designing interfaces and base classes in object-oriented programming. This is a common subject in c++ basic interview questions.

How to answer:

Explain that an abstract class is a class that has at least one pure virtual function (declared with =0). It cannot be instantiated directly and serves as a base for derived classes to implement those pure virtual functions.

Example answer:

"An abstract class is a class that contains at least one pure virtual function, which is a virtual function declared with = 0. Because it has a pure virtual function, you can't create objects directly from an abstract class. Instead, it acts as a blueprint or an interface that derived classes must implement. For example, if I have an abstract class called 'Shape' with a pure virtual function 'area()', any class that inherits from 'Shape' like 'Circle' or 'Rectangle' must provide its own implementation of the 'area()' function. Abstract classes are crucial for defining common interfaces in object-oriented systems."

## 10. What is the difference between class and struct?

Why you might get asked this:

This question tests your understanding of the subtle differences between classes and structs in C++. It’s a common point of confusion for beginners. This falls squarely within the realm of c++ basic interview questions.

How to answer:

Explain that in C++, struct and class are almost the same except that by default, members of a struct are public, whereas members of a class are private.

Example answer:

"In C++, structs and classes are very similar. The key difference is that the default access specifier for members in a struct is public, while for a class, it's private. This means that if you don't explicitly specify the access level of a member in a struct, it will be accessible from anywhere. In a class, you need to explicitly declare members as public to make them accessible from outside the class. Essentially, they serve the same purpose; the only difference is the default visibility. Often, I use structs for simple data structures where I want all members to be publicly accessible, and classes for more complex objects with encapsulated data."

## 11. Explain the concept of polymorphism in C++.

Why you might get asked this:

This question assesses your understanding of polymorphism, a fundamental concept in object-oriented programming. Interviewers want to see if you know how to write flexible and extensible code. Polymorphism is a key topic in c++ basic interview questions.

How to answer:

Explain that polymorphism allows functions or methods to behave differently based on the object that invokes them, commonly implemented via virtual functions and inheritance, enabling dynamic binding.

Example answer:

"Polymorphism, which literally means 'many forms', allows objects of different classes to be treated as objects of a common type. This is usually achieved through inheritance and virtual functions. For example, if you have a base class 'Animal' with a virtual function 'makeSound()', derived classes like 'Dog' and 'Cat' can override this function to produce different sounds. This way, you can call 'makeSound()' on an array of 'Animal' objects, and each object will produce its specific sound. Polymorphism makes code more flexible and extensible, allowing you to write code that works with objects of different types in a uniform way."

## 12. What is a virtual function?

Why you might get asked this:

This question tests your understanding of virtual functions and their role in achieving runtime polymorphism. It's an important concept for understanding object-oriented design. Understanding virtual functions is essential when addressing c++ basic interview questions.

How to answer:

Explain that a virtual function is a member function declared with the keyword virtual in the base class that can be overridden in derived classes to achieve runtime polymorphism.

Example answer:

"A virtual function is a member function in a base class that you expect to be redefined in derived classes. You declare it using the virtual keyword. When you call a virtual function through a base class pointer or reference, the actual function that gets executed is determined at runtime based on the type of the object being pointed to or referenced. This is how you achieve runtime polymorphism. I recall a scenario where using virtual functions allowed me to process different types of graphical objects uniformly, even though they had distinct rendering behaviors. So, virtual functions are critical for achieving dynamic behavior in object-oriented C++."

## 13. What is the size of void in C++?

Why you might get asked this:

This question checks your understanding of the void type and its purpose in C++. It's a more conceptual question that tests your understanding of type systems. Many c++ basic interview questions involve understanding types.

How to answer:

Explain that void does not have a size since it represents the absence of type. However, a pointer to void has a size appropriate to pointers on the system architecture.

Example answer:

"void itself doesn't have a size because it represents the absence of a specific type. It's used to indicate that a function doesn't return a value or that a pointer is a generic pointer that can point to any data type. However, a pointer to void, void, does have a size, which is the size of a memory address on the system. This allows void to point to any memory location, regardless of the data type stored there. So, while void itself has no size, void* has a size equivalent to any other pointer type on the architecture."

## 14. What is the difference between pointers and references?

Why you might get asked this:

This question tests your understanding of pointers and references, which are fundamental for memory management and data manipulation in C++. This is a core topic covered in c++ basic interview questions.

How to answer:

Explain that pointers are variables that hold memory addresses and can be reassigned, whereas references are aliases to existing variables and must be initialized when declared and cannot be reseated.

Example answer:

"Pointers and references are both used to indirectly access data, but they have key differences. A pointer holds the memory address of a variable and can be reassigned to point to different variables. You can also perform arithmetic operations on pointers. On the other hand, a reference is an alias for an existing variable and must be initialized when declared. Once initialized, a reference cannot be reseated to refer to a different variable. Pointers can be null, whereas references are guaranteed to refer to a valid object. I find references cleaner and safer to use when I don't need to reassign or perform pointer arithmetic, while pointers are more flexible when you need to manipulate memory addresses directly."

## 15. What is call by value and call by reference?

Why you might get asked this:

This question checks your understanding of how arguments are passed to functions in C++. It's important for understanding how functions interact with variables. This is an often-addressed topic among c++ basic interview questions.

How to answer:

Explain that call by value passes a copy of the argument to the function, so changes don't affect the original variable. Call by reference passes the actual variable, allowing the function to modify it.

Example answer:

"Call by value and call by reference are two ways of passing arguments to a function. With call by value, a copy of the argument is passed to the function, so any modifications made to the argument inside the function do not affect the original variable outside the function. With call by reference, a reference to the original variable is passed to the function, allowing the function to directly modify the original variable. Choosing between call by value and call by reference depends on whether you want the function to modify the original variable or not. Call by value is safer when you don't want the function to change the original variable, while call by reference is more efficient when you need to modify the original variable directly."

## 16. Explain encapsulation in C++.

Why you might get asked this:

This question assesses your understanding of encapsulation, a fundamental principle of object-oriented programming. Interviewers want to see if you know how to protect data and control access to it. Encapsulation is a key component of many c++ basic interview questions.

How to answer:

Explain that encapsulation is the bundling of data (variables) and methods that operate on the data into a single unit or class, restricting direct access to some of the object's components to protect integrity.

Example answer:

"Encapsulation is one of the core principles of object-oriented programming. It involves bundling data and methods that operate on that data within a single unit, typically a class. The idea is to hide the internal state of an object and protect it from outside access, exposing only a well-defined interface for interacting with the object. This helps to prevent accidental corruption of data and makes the code more modular and maintainable. For example, in a class representing a bank account, the account balance would be a private member variable, and you would provide public methods like 'deposit()' and 'withdraw()' to access and modify the balance in a controlled way. Encapsulation promotes data hiding and helps create more robust and maintainable code."

## 17. What are constructors and destructors?

Why you might get asked this:

This question checks your understanding of constructors and destructors, which are essential for object initialization and cleanup in C++. They are key when understanding c++ basic interview questions.

How to answer:

Explain that constructors are special class functions that initialize objects when created. Destructors are functions called automatically when an object is destroyed to free resources.

Example answer:

"Constructors and destructors are special member functions in C++ classes. A constructor is automatically called when an object of the class is created. It's used to initialize the object's state and can take arguments to customize the initialization. A destructor, on the other hand, is automatically called when an object is destroyed. It's used to release any resources that the object may have acquired during its lifetime, such as dynamically allocated memory. For instance, a constructor might allocate memory for a string, and the destructor would free that memory to prevent memory leaks. Constructors and destructors ensure that objects are properly initialized and cleaned up, which is crucial for writing reliable C++ code."

## 18. Explain the difference between shallow copy and deep copy.

Why you might get asked this:

This question tests your understanding of shallow and deep copies, which are important concepts when dealing with dynamically allocated memory and object copying. Understanding how to handle object copies is essential when addressing c++ basic interview questions.

How to answer:

Explain that a shallow copy copies an object's values, including pointers, leading to shared referenced data. A deep copy duplicates the pointed-to data in separate memory locations to prevent unintended sharing.

Example answer:

"The difference between a shallow copy and a deep copy comes down to how they handle pointers. A shallow copy simply copies the values of the object's members, including the values of any pointers. This means that the original object and the copied object will both point to the same memory locations. If one object modifies the data at those memory locations, the changes will be visible to the other object. A deep copy, on the other hand, creates new memory locations for the data pointed to by the pointers and copies the data to those new locations. This means that the original object and the copied object will have their own independent copies of the data. I once had a bug because I was using shallow copy instead of deep copy, leading to unexpected data corruption. So, the choice depends on whether you want the copied object to share data with the original object or have its own independent copy."

## 19. What are templates in C++?

Why you might get asked this:

This question assesses your understanding of templates, which are a powerful feature for writing generic code in C++. Interviewers want to see if you know how to write code that works with different data types. Templates are a more advanced topic in c++ basic interview questions.

How to answer:

Explain that templates allow writing generic functions or classes that work with any data type, enabling code reuse. Give an example, such as template class MyClass { ... }.

Example answer:

"Templates in C++ allow you to write code that can work with different data types without having to write separate versions for each type. They are a form of generic programming. You can create template functions or template classes. The template parameter, often denoted by typename T, acts as a placeholder for a data type that will be specified later when the template is used. For example, you can create a template function to sort an array, and it will work with arrays of integers, floats, or any other comparable type. Templates promote code reuse and reduce code duplication. In a project, I used templates to create a generic data structure that could store different types of data, which greatly simplified the code and made it more maintainable."

## 20. What is a namespace?

Why you might get asked this:

This question checks your understanding of namespaces and how they are used to avoid name conflicts in C++. It's an important concept for organizing code in large projects. Namespaces are foundational when discussing c++ basic interview questions.

How to answer:

Explain that a namespace groups entities like classes and functions under a name to avoid name conflicts, especially in large projects or libraries (e.g., std namespace).

Example answer:

"A namespace is a declarative region that provides a scope to the names inside it. In other words, a namespace groups related classes, functions, variables, and other entities under a single name. This helps to avoid name collisions, especially in large projects or when using third-party libraries. For example, the C++ Standard Library is enclosed in the std namespace. So, when you use cout, you're actually using std::cout. Namespaces help organize code and prevent naming conflicts, making code more manageable and maintainable, especially as projects grow in size and complexity."

## 21. What is the use of the const keyword?

Why you might get asked this:

This question assesses your understanding of the const keyword and its role in creating const-correct code. Interviewers want to see if you know how to prevent accidental modification of data. const is a fundamental concept when reviewing c++ basic interview questions.

How to answer:

Explain that const is used to declare variables or pointers as unmodifiable after initialization, providing const-correctness and safer code.

Example answer:

"The const keyword is used to specify that a variable or function parameter should not be modified after initialization. When you declare a variable as const, you're telling the compiler that its value should not be changed. This helps prevent accidental modifications and makes the code more robust. You can also use const with pointers to indicate that the pointer itself or the data it points to is constant. Similarly, you can use const with member functions to indicate that the function does not modify the object's state. Using const correctly can improve code safety and readability by making it clear which values are intended to remain unchanged."

## 22. What is the difference between stack and heap memory?

Why you might get asked this:

This question tests your understanding of memory management in C++. Interviewers want to see if you know how memory is allocated and deallocated. Memory management is an essential part of c++ basic interview questions.

How to answer:

Explain that stack memory is used for static memory allocation and function calls; it is fast and automatically managed. Heap memory is for dynamic allocation, managed manually by the programmer via new and delete.

Example answer:

"The stack and the heap are two different regions of memory used by a program. The stack is used for static memory allocation, such as local variables and function call information. Memory on the stack is automatically managed, and it's very fast to allocate and deallocate. The heap, on the other hand, is used for dynamic memory allocation. You allocate memory on the heap using new and deallocate it using delete. Heap memory is managed manually by the programmer, so it's important to be careful to avoid memory leaks. The stack is typically smaller than the heap, and it's limited by the system's resources. I had to debug a memory leak issue once, and the culprit was improper heap memory management. So, understanding the difference and proper usage is really critical."

## 23. What is a pure virtual function?

Why you might get asked this:

This question checks your understanding of pure virtual functions and abstract classes, which are important for designing interfaces and base classes. Understanding virtual functions is a key element to many c++ basic interview questions.

How to answer:

Explain that a pure virtual function is declared by assigning 0 in its declaration (e.g., virtual void foo() = 0;). It makes a class abstract and forces derived classes to provide an implementation.

Example answer:

"A pure virtual function is a virtual function that is declared but not defined in a base class. It is declared by assigning 0 to the function in the class definition, like this: virtual void foo() = 0;. When a class contains at least one pure virtual function, it becomes an abstract class. You cannot create objects of an abstract class directly. Instead, you must create derived classes that provide concrete implementations for all the pure virtual functions. Pure virtual functions are used to define interfaces that derived classes must implement. It ensures that derived classes provide specific functionality."

## 24. What is the meaning of inline function?

Why you might get asked this:

This question assesses your understanding of inline functions and their role in optimizing code performance. It’s important to be aware of performance considerations when addressing c++ basic interview questions.

How to answer:

Explain that an inline function suggests to the compiler to insert the function code at the call site to reduce function call overhead, improving performance.

Example answer:

"An inline function is a function that the compiler can choose to replace the function call with the actual code of the function at the call site. This eliminates the overhead of a function call, such as pushing arguments onto the stack and jumping to the function's address. The inline keyword is a suggestion to the compiler, and the compiler may choose to ignore it if it deems that inlining the function would not be beneficial. Inline functions are typically used for small, frequently called functions to improve performance. I've used inline functions in situations where I needed to optimize performance-critical sections of code, and it can sometimes provide a noticeable improvement."

## 25. What is the difference between new and malloc?

Why you might get asked this:

This question tests your understanding of memory allocation in C++ and the differences between new and malloc. Understanding memory allocation is a vital component of c++ basic interview questions.

How to answer:

Explain that new allocates memory and calls the constructor, returning a typed pointer. malloc only allocates memory and returns a void pointer; constructors are not called.

Example answer:

"new and malloc are both used for dynamic memory allocation, but they differ in several important ways. new is a C++ operator that allocates memory and also calls the constructor of the object being created. It returns a pointer of the correct type. malloc, on the other hand, is a C function that only allocates memory and returns a void*, which you then need to cast to the appropriate type. Importantly, malloc does not call constructors. Also, new can be overloaded for custom memory management, while malloc cannot. When you use new, you should use delete to free the memory, and when you use malloc, you should use free. I prefer new because it's type-safe and calls constructors, ensuring that objects are properly initialized."

## 26. How does exception handling work in C++?

Why you might get asked this:

This question assesses your understanding of exception handling, which is important for writing robust and error-tolerant code. This is an important aspect of c++ basic interview questions.

How to answer:

Explain that C++ uses try, catch, and throw blocks to handle exceptions. Code that might throw an exception goes in try, exceptions are thrown by throw, and handled by catch blocks.

Example answer:

"C++ uses a mechanism called exception handling to deal with errors that occur during runtime. The key components are try, catch, and throw. You put the code that might throw an exception inside a try block. If an exception occurs, it's thrown. Then, one or more catch blocks are used to handle the exception. Each catch block specifies the type of exception it can handle. When an exception is thrown, the runtime system looks for the first matching catch block to handle it. Exception handling allows you to write code that can gracefully recover from errors and prevent the program from crashing. I've used exception handling to manage file I/O errors, network connection issues, and other potential problems."

## 27. What is function overloading?

Why you might get asked this:

This question checks your understanding of function overloading, which allows you to define multiple functions with the same name but different parameters. Understanding overloading and overriding is key when addressing c++ basic interview questions.

How to answer:

Explain that function overloading allows multiple functions with the same name but different parameters in the same scope, enabling different behaviors depending on argument types or counts.

Example answer:

"Function overloading allows you to define multiple functions with the same name in the same scope, as long as they have different parameter lists (different number, types, or order of parameters). This allows you to provide different implementations of a function that can handle different types of input. For example, you can have multiple print functions: one that takes an integer, one that takes a float, and one that takes a string. The compiler will choose the appropriate function to call based on the arguments you pass to it. Function overloading makes code more flexible and easier to use by allowing you to use the same function name for operations that are conceptually similar but operate on different types of data."

## 28. What is the difference between overloading and overriding?

Why you might get asked this:

This question tests your understanding of overloading and overriding, which are related but distinct concepts in C++. Interviewers want to see if you understand the difference between compile-time and runtime polymorphism. Solid understanding of this concepts is key when addressing c++ basic interview questions.

How to answer:

Explain that overloading means functions have the same name but different signatures; overriding means a derived class provides a new implementation of a virtual function declared in the base class.

Example answer:

"Overloading and overriding are two distinct concepts related to polymorphism. Overloading refers to the ability to have multiple functions with the same name but different signatures (parameter lists) within the same scope. The compiler resolves which function to call at compile time based on the arguments provided. Overriding, on the other hand, occurs when a derived class provides a new implementation for a virtual function that is declared in the base class. Overriding is a form of runtime polymorphism, where the correct function to call is determined at runtime based on the actual type of the object. So, overloading is about providing multiple functions with the same name but different parameters, while overriding is about providing a new implementation for a virtual function in a derived class."

## 29. What are smart pointers?

Why you might get asked this:

This question assesses your understanding of smart pointers and their role in managing memory automatically. It's a more advanced topic, related to preventing memory leaks. Understanding memory management is a key aspect of c++ basic interview questions.

How to answer:

Explain that smart pointers like std::uniqueptr, std::sharedptr manage heap-allocated objects automatically, handling memory deallocation when no longer referenced to avoid leaks.

Example answer:

"Smart pointers are classes that act like pointers but provide automatic memory management. They are designed to prevent memory leaks by ensuring that dynamically allocated memory is automatically deallocated when it's no longer needed. C++ provides several types of smart pointers, including std::uniqueptr, std::sharedptr, and std::weakptr. uniqueptr provides exclusive ownership of the managed object, sharedptr allows multiple pointers to share ownership, and weakptr provides a non-owning reference to an object managed by a shared_ptr. Using smart pointers promotes safer and more robust code by automating memory management and reducing the risk of memory leaks and dangling pointers."

## 30. What is the output of this program snippet?

Why you might get asked this:

This question tests your understanding of operator precedence and undefined behavior in C++. Interviewers want