abstract override

using System.Collections.Generic;
using System.Linq;
using System.Text;
using System;

namespace VirtualFunctionApplication {
   
 
   
    abstract class Base  {
     
        public  Base() {
            Console.WriteLine("This is base class");
        }
        public abstract void func();
      }
    
    class Derivative : Base {
        public  Derivative() {
            Console.WriteLine("This is Derivative class");
        }
        public override void func(){
            Console.WriteLine("This is base override function");
            
        }
        
    }
      
   
   
   class MainClass {
     
      static void Main(string[] args) {
        Base b = new Derivative();
        b.func();
      }
   }
}