Ans. Stack memory is used for static memory allocation and is automatically managed. Heap memory is used for dynamic memory allocation and must be manually managed using new and delete in C++.

Ans. The this pointer is an implicit pointer available in non-static member functions of a class. It points to the object for which the member function is called.

Ans. Access specifiers define the scope of class members. C++ has three: public (accessible anywhere), private (accessible only within the class), and protected (accessible in the class and its derived classes).

Ans. Operator overloading allows you to redefine the way operators work for user-defined types (classes). For example, you can overload the + operator to add two objects.

Ans. Function overloading is when multiple functions have the same name but different parameters. The correct function is chosen based on the arguments passed.

Ans. A virtual function is a member function in a base class that can be overridden in a derived class. It enables runtime polymorphism.

Ans. A pure virtual function is a function declared in a base class with = 0. It must be overridden by derived classes. A class with at least one pure virtual function is called an abstract class.

Ans. An abstract class in C++ is a class that cannot be instantiated and contains at least one pure virtual function.

Ans. A namespace is a declarative region that provides a scope to identifiers to avoid name conflicts. The standard C++ library uses the std namespace.

Ans. Exception handling allows you to handle runtime errors using try, catch, and throw blocks, preventing crashes and enabling graceful error handling.

Ans. Templates allow writing generic programs. You can write a function or class that works with any data type using template<typename T>.

Ans. In C++, both can have member functions, but the default access specifier in struct is public, while in class it is private.

Ans. Static members belong to the class, not any object. They are shared among all instances and are accessed using the class name.

Ans. A memory leak occurs when dynamically allocated memory is not properly released using delete, leading to memory being wasted.

Ans. A shallow copy copies only the pointer value, not the data it points to. A deep copy creates a new copy of the data as well, preventing shared references.

Ans. A friend function or class can access private and protected members of another class in which it is declared a friend.

Ans. Function overriding occurs when a derived class provides a specific implementation of a virtual function defined in a base class.

Ans. The mutable keyword allows a member of an object to be modified even if the object is declared as const.

Ans. Smart pointers like std::unique_ptr, std::shared_ptr, and std::weak_ptr automatically manage dynamic memory, reducing memory leaks.

Ans. new and delete are C++ operators that also call constructors and destructors. malloc and free are C-style functions that do not call constructors/destructors and should be avoided in C++.

Ans. An inline function suggests the compiler to insert the complete function code at the point of function call to reduce overhead of function call.

Ans. A pointer can be reassigned and can be NULL, while a reference must be initialized when declared and cannot be changed to refer to another object.

Ans. RAII (Resource Acquisition Is Initialization) is a programming idiom where resource allocation is tied to object lifetime, ensuring proper release in destructors.

Ans. Compile-time polymorphism is achieved via function overloading and operator overloading. Runtime polymorphism is achieved using virtual functions.

Ans. The explicit keyword prevents the compiler from using a constructor for implicit conversions.

Ans. A dangling pointer is a pointer that points to memory that has been deallocated or deleted.

Ans. STL is a library of generic classes and functions including containers (like vector, list), algorithms, and iterators.

Ans. Iterators are objects used to traverse through the elements of STL containers like vectors and lists.

Ans. An array has a fixed size and is not resizable, while a vector is dynamic and can grow or shrink during runtime.

Ans. const_cast is used to add or remove the const qualifier from a variable.

Ans. dynamic_cast is used for safe downcasting in class hierarchies with polymorphism. It returns nullptr if the cast is invalid.

Ans. static_cast is used for conversions between related types like int to float or base to derived class pointers (if safe).

Ans. reinterpret_cast is used for low-level reinterpreting of bit patterns, like converting an int pointer to a float pointer.

Ans. throw is used to raise an exception, while noexcept is a specifier that indicates a function does not throw exceptions.

Ans. Function pointers are used to store the address of a function. They can be used to call functions dynamically.

Ans. Lambda expressions allow you to define anonymous functions in place, useful especially with STL algorithms.

Ans. The auto keyword lets the compiler automatically deduce the variable's type from its initializer.

Ans. The scope resolution operator :: is used to define functions outside a class or to access global variables or class members.

Ans. Bitwise operators operate on bits and include AND (&), OR (|), XOR (^), NOT (~), left shift (<<), and right shift (>>).

Ans. Pre-increment (++i) increments the value before using it, while post-increment (i++) uses the value first and then increments.

Ans. Prefix (++i) increments the value before use, while postfix (i++) increments the value after use. Example: int a = 5; int b = ++a; makes b = 6; int c = a++; makes c = 6, a = 7.

Ans. C++ supports single, multiple, multilevel, hierarchical, and hybrid inheritance.

Ans. A constructor is a special member function automatically called when an object is created. It initializes the object.

Ans. A copy constructor is used to create a new object as a copy of an existing object. Syntax: ClassName(const ClassName &obj).

Ans. If a class defines a destructor, copy constructor, or copy assignment operator, it should define all three to manage resources properly.

Ans. Overloading means having multiple functions with the same name but different parameters. Overriding means redefining a base class’s virtual function in a derived class.

Ans. The explicit keyword prevents automatic and implicit conversions. It is used with single-argument constructors to avoid unexpected conversions.

Ans. const is used to make variables read-only. It can also be applied to function parameters and member functions to prevent modification.

Ans. A pointer can be reassigned and can be null. A reference must be initialized when declared and cannot be changed to refer to another object.

Ans. RAII (Resource Acquisition Is Initialization) is a C++ programming idiom where resource allocation is tied to object lifetime, ensuring resources are released when the object goes out of scope.

Ans. Macros are defined using #define and replaced by the preprocessor before compilation. They are not type-safe and should be used carefully.

Ans. The inline keyword suggests to the compiler to insert the function code directly into the caller’s code to reduce overhead of function calls.

Ans. Dynamic dispatch is the process of selecting which implementation of a polymorphic function to call at runtime, enabled by virtual functions in C++.

Ans. static_cast is used for compile-time type conversions. dynamic_cast is used for safe downcasting in polymorphic class hierarchies and requires RTTI.

Ans. The typeid operator is used to determine the type of an object at runtime. It returns a type_info object containing the type name.

Ans. STL (Standard Template Library) provides generic classes and functions including containers (vector, list), algorithms (sort, find), and iterators.

Ans. Iterators are objects that point to elements in containers and allow traversal using operators like * and ++.

Ans. A lambda function is an anonymous function that can capture variables from the surrounding scope and can be used as a callback or inline logic.

Ans. Move semantics allow the resources of one object to be moved to another instead of copied, improving performance. It uses rvalue references (&&).

Ans. std::move is a cast that turns an object into an rvalue, enabling move semantics. It does not actually move data; it only allows moving.

Ans. A class is a blueprint for creating objects. An object is an instance of a class, representing a real-world entity with state and behavior.

Ans. A virtual destructor ensures the correct destructor is called for derived classes when an object is deleted through a base class pointer.

Ans. An initializer list is used in constructors to initialize class members directly before the constructor body executes.

Ans. Function hiding occurs when a derived class defines a function with the same name as a base class function, hiding all overloaded versions in the base class.

Ans. The volatile keyword tells the compiler not to optimize a variable, as it may change unexpectedly, often used in multithreading or hardware access.

Ans. An enum (enumeration) is a user-defined type consisting of a set of named integral constants, improving code readability and maintainability.

Ans. Name mangling is the process by which C++ encodes function and variable names to support function overloading and namespaces.

Ans. lvalues refer to memory locations and can appear on the left side of an assignment. rvalues are temporary and cannot be assigned to.

Ans. std::vector is a dynamic array provided by the STL that can grow or shrink in size and offers random access to elements.

Ans. push_back() adds a copy of an element, while emplace_back() constructs the element in place, improving performance by avoiding unnecessary copies.

Ans. A functor is an object that acts like a function. It overloads the () operator and can maintain state across calls.

Ans. A segmentation fault occurs when a program tries to access a restricted or unallocated area of memory, often due to pointer errors.

Ans. In public inheritance, base class public/protected members retain their access level. In protected, public becomes protected. In private, both become private.

Ans. std::map is an associative container that stores key-value pairs in sorted order. Each key is unique and mapped to a value.

Ans. Type casting is converting one data type to another. C++ supports static_cast, dynamic_cast, const_cast, and reinterpret_cast.

Ans. std::pair is a container that stores two heterogeneous objects as a single unit. It's useful for returning multiple values from functions.

Ans. delete is used for single object deallocation. delete[] is used to deallocate arrays. Using the wrong one can cause undefined behavior.

Ans. std::move_if_noexcept moves an object only if the move constructor is noexcept; otherwise, it copies the object to avoid exceptions.

Ans. The diamond problem occurs in multiple inheritance when two base classes inherit from the same base, and a class inherits from both. It’s solved using virtual inheritance.

Ans. std::unique_ptr is a smart pointer that owns and manages a dynamically allocated object. It ensures single ownership and deletes the object when out of scope.

Ans. The typeid operator is used to get type information at runtime. It returns a reference to a type_info object representing the type of the expression.

Ans. A lambda expression is an anonymous function that can capture variables from the surrounding scope. It is useful for short, inline function definitions.

Ans. A functor is a class that overloads the operator(), making its instances callable like regular functions.

Ans. If a class needs a user-defined destructor, copy constructor, or copy assignment operator, it likely needs all three. This is called the Rule of Three.

Ans. The Rule of Five extends the Rule of Three to include the move constructor and move assignment operator introduced in C++11.

Ans. constexpr declares that a variable or function can be evaluated at compile time, improving performance and enabling compile-time computation.

Ans. const means a variable cannot be modified after initialization. constexpr means the variable or function can be evaluated at compile time.

Ans. std::move is used to cast an object to an rvalue reference, enabling move semantics to avoid unnecessary copying.

Ans. Rvalue references (denoted as T&&) bind to temporary objects and are used in move semantics to optimize performance.

Ans. A delegate constructor calls another constructor of the same class to avoid code duplication.

Ans. std::array is a fixed-size array container introduced in C++11 that encapsulates a C-style array and provides STL functionalities.

Ans. std::vector provides fast random access and is contiguous in memory. std::list is a doubly linked list providing efficient insertions/deletions but no random access.

Ans. RAII (Resource Acquisition Is Initialization) is a programming idiom where resource allocation is tied to object lifetime, ensuring proper cleanup via destructors.

Ans. noexcept specifies that a function does not throw exceptions. It allows better optimization and exception guarantees.

Ans. push_back copies or moves an existing object into a container. emplace_back constructs the object in-place using constructor arguments.

Ans. The diamond problem occurs in multiple inheritance when two base classes inherit from the same base class, causing ambiguity. It is resolved using virtual inheritance.

Ans. A virtual destructor ensures that the destructor of the derived class is called when deleting an object through a base class pointer.

Ans. Prefix increments the value and returns the updated value. Postfix returns the original value and then increments it.

Ans. std::map is an ordered associative container implemented as a balanced binary tree. std::unordered_map is an unordered associative container implemented using hash tables.

Ans. std::tie is used to unpack tuples or pair values into individual variables, typically used in structured bindings or comparisons.