How to inherit a class in C#?

Inheritance allows us to define a class in terms of another class, which makes it easier to create and maintain an application.

When creating a class, instead of writing completely new data members and member functions, the programmer can designate that the new class should inherit the members of an existing class. This existing class is called the base class, and the new class is referred to as the derived class. 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.

Let us see an example −

Example

 Live Demo

using System;

namespace InheritanceApplication {
   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