C++ Interview Questions and Answers
Question 1:
What is C++?
C++ is a general-purpose programming language that extends the C programming language with additional features. It is an object-oriented programming language known for its efficiency, flexibility, and wide range of applications. C++ supports procedural, object-oriented, and generic programming paradigms and provides features such as classes, templates, and exceptions.
Question 2:
What are the key features of C++?
C++ offers several key features, including:
- Object-Oriented Programming: C++ supports the concepts of classes, objects, inheritance, and polymorphism, allowing for modular and reusable code.
- Strong Typing: C++ enforces strong typing, which means that the type of every expression is checked at compile time, leading to safer and more reliable code.
- Template Metaprogramming: C++ templates enable generic programming, allowing for the creation of reusable algorithms and data structures.
- Exception Handling: C++ provides mechanisms for handling exceptional conditions, allowing developers to write code that gracefully handles and recovers from errors.
- Low-Level Manipulation: C++ allows low-level memory management, direct access to hardware, and fine-grained control over system resources, making it suitable for systems programming and performance-critical applications.
Question 3:
What is the difference between C and C++?
C and C++ are both programming languages, but they have some key differences:
- Object-Oriented Programming: C++ is an extension of C with additional features, including support for object-oriented programming, while C is a procedural programming language.
- Standard Libraries: C++ provides the Standard Template Library (STL), which includes various data structures and algorithms, whereas C does not have a standard library of this kind.
- Function Overloading: C++ allows function overloading, which means you can have multiple functions with the same name but different parameter lists, while C does not support function overloading.
- Exceptions: C++ supports exception handling, allowing for more robust error handling, while C does not have built-in support for exceptions.
- Compatibility: C++ is mostly backward-compatible with C, meaning that most C programs can be compiled and executed in C++, but not vice versa.
Question 4:
What are the different data types in C++?
C++ provides several built-in data types, including:
- Primitive Types: Integers (int, short, long), floating-point numbers (float, double), characters (char), and boolean (bool).
- Derived Types: Arrays, pointers, references, and function types.
- User-Defined Types: Classes, structures, and enumerations.
Question 5:
What is the difference between pass-by-value and pass-by-reference?
- Pass-by-Value: Pass-by-value is a method of passing arguments to a function where the values of the arguments are copied into the function parameters. Any modifications made to the function parameters do not affect the original values of the arguments.
- Pass-by-Reference: Pass-by-reference is a method of passing arguments to a function where the memory address of the arguments is passed instead of their values. Any modifications made to the function parameters affect the original values of the arguments outside the function.
Question 6:
What is inheritance in C++?
Inheritance is a key feature of object-oriented programming that allows a class to inherit properties and behaviors from another class. The class that inherits is called the derived class or subclass, and the class from which it inherits is called the base class or superclass. In C++, inheritance is specified using the "class" keyword followed by a colon and the access specifier, followed by the base class name. Inheritance facilitates code reuse, modularity, and the creation of class hierarchies.
Question 7:
What is the difference between function overloading and function overriding?
- Function Overloading: Function overloading is a feature in C++ that allows multiple functions with the same name but different parameter lists. The compiler distinguishes between overloaded functions based on the number, types, or order of parameters. Function overloading is resolved at compile time.
- Function Overriding: Function overriding occurs in a derived class when a function with the same name and signature as a base class function is defined. It allows the derived class to provide its own implementation of the function. Function overriding is resolved at runtime through virtual functions and dynamic binding.
Question 8:
What is the difference between a class and an object in C++?
- Class: A class is a blueprint or a template that defines the structure, properties, and behaviors of objects. It defines the data members and member functions that objects of the class will have.
- Object: An object is an instance of a class. It represents a specific occurrence or realization of the class, with its own set of data and behavior. Objects are created from classes and can interact with each other through methods and attributes.
Question 9:
What are constructors and destructors in C++?
- Constructors: Constructors are special member functions in a class that are called automatically when an object of the class is created. They initialize the object's data members and perform any necessary setup operations. Constructors have the same name as the class and do not have a return type.
- Destructors: Destructors are special member functions in a class that are called automatically when an object of the class is destroyed or goes out of scope. They perform cleanup operations, such as releasing resources or deallocating memory, before the object is destroyed. Destructors have the same name as the class preceded by a tilde (~) and do not take any arguments.
Question 10:
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div class="question">What is the difference between stack and heap memory in C++?
- Stack Memory: Stack memory is a region of memory that is used for storing local variables and function call information. It is managed by the compiler and automatically allocated and deallocated as functions are called and return. Stack memory is fast but limited in size, and the memory allocation is determined at compile time.
- Heap Memory: Heap memory is a region of memory that is used for dynamic memory allocation. It is managed by the programmer and allows for the allocation and deallocation of memory blocks at runtime. Heap memory is larger but slower than stack memory, and the memory allocation is determined at runtime using functions such as "new" and "delete".