using System;

​

struct Books {

   public string title;

   public string author;

   public string subject;

   public int book_id;

}; 

​

public class Program

{

    public static void Main()

    {

        Books books; 

        books.title = "Wings of Fire";

        books.author = "APJ Abdhul Kalam";

        books.subject = "Auto Biography";

        books.book_id = 1;

        double?d = 22.5;

        int i = (int)d;

        float ii = (float)d;

        Console.WriteLine("Hello World {0}", books.author);

        Program n = new Program();

        n.printLoop();

    }

    public void printLoop(){

        for(int a=0; a<50;a++){

            Console.WriteLine("Looping a {0}",a);

        }

    }

}