using System;

public class Program

{

 public static void Main()

 {

  double radius = 5.0;

        double diameter = GetCircleDiameter(radius);

        Console.WriteLine("The diameter of the circle is " + diameter);

        Product product = new Product { code = "P001", description = "Product 1", price = 100.0 };

        Console.WriteLine("Product Code: " + product.code + ", Description: " + product.description + ", Price: " + product.price);

        Person person = new Person();

        Console.WriteLine("Person's full name is " + person.full_name);

        Accounts.Account account = new Accounts.Account { account_number = "A001" };

        Console.WriteLine("Account number is " + account.account_number);

 }

 public static double GetCircleDiameter(double radius)

 {

 return 2 * radius;

 }

}

​

 public struct Product

 {

 public string code;

 public string description;

 public double price;

 }

public class Person

{

 public string full_name;

 public Person()

 {

 full_name = "Default Name";

 }

}

​

namespace Accounts

{

 public class Account

 {

 public string account_number;

 }

}