What are Base and Derived Classes in C#?

A class can be derived from more than one class or interface, which means that it can inherit data and functions from multiple base classes or interfaces.

For example, Vehicle Base class with the following Derived Classes.

Truck
Bus
Motobike

The derived class inherits the base class member variables and member methods.

In the same way, the derived class for Shape class can be Rectangle as in the following example.

Example

 Live Demo

using System;
namespace Program {
   class Shape {
      public void setWidth(int w) {
         width = w;
      }
      public void setHeight(int h) {
         height = h;
      }
      protected int width;
      protected int height;
   }
   // Derived class
   class Rectangle: Shape {
      public int getArea() {
         return (width * height);
      }
   }
   class Demo {
      static void Main(string[] args) {
         Rectangle Rect = new Rectangle();
         Rect.setWidth(5);
         Rect.setHeight(7);
         // Print the area of the object.
         Console.WriteLine("Total area: {0}", Rect.getArea());
         Console.ReadKey();
      }
   }
}

Output

Total area: 35