What is a base class and derived class?

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The base class is a class whose members and functions can be inherited, and the derived class is the class that inherits those members and may also have additional properties.

In .NET programming, a base class and a derived class are fundamental concepts in object-oriented programming (OOP). Here’s a breakdown of each:

  1. Base Class:
    • A base class, also known as a parent class or superclass, serves as the foundation or starting point for other classes.
    • It defines common attributes, properties, methods, and behaviors that are shared by one or more derived classes.
    • Base classes are not meant to be instantiated on their own but are intended to be inherited by other classes.
    • In C#, the base class is declared using the class keyword, followed by the class name and its members.
  2. Derived Class:
    • A derived class, also known as a child class or subclass, is a class that inherits properties and behavior from its base class.
    • It extends the functionality of the base class by adding new attributes, properties, methods, or by modifying existing ones.
    • A derived class can also provide its own unique implementation of methods defined in the base class, through a process called method overriding.
    • Derived classes can further serve as base classes for other classes, creating a hierarchical structure of classes.
    • In C#, a derived class is declared using the class keyword followed by the class name, a colon, and the name of the base class from which it inherits.

Example in C#:

csharp
// Base Class
public class Animal
{
public void Eat()
{
Console.WriteLine("Animal is eating.");
}
}

// Derived Class
public class Dog : Animal
{
public void Bark()
{
Console.WriteLine("Dog is barking.");
}
}

class Program
{
static void Main(string[] args)
{
Dog myDog = new Dog();
myDog.Eat(); // This method is inherited from the base class
myDog.Bark(); // This method is specific to the derived class
}
}

In this example, Animal is the base class, and Dog is the derived class. The Dog class inherits the Eat() method from the Animal class and adds its own method Bark(). Instances of the Dog class can access both inherited and derived methods.