inheritance.cs

using System;

// Base class
class Shape {
   public Shape(){length = 0;} //default constructor
   public void setlength(int l) {length = l;}
   protected int length;
}

// Derived class
class Sqaure: Shape {
   public Sqaure()  {length = 0;} //declaring and initializing derived class constructor
   public int get_Area(){ return (length * length); }
}

class Program
{
  static void Main(){
   Sqaure sq = new Sqaure(); //making object of child class Sqaure
   sq.setlength(5); //setting length equal to 5
   // Print the area of the object.
   Console.WriteLine("Total area of sqaure is: {0}",sq.get_Area());
  }
}