Armstrong number between 100 to 500

Write a program in c# (c sharp) to  find out the Armstrong Numbers between series of  100 -500 numbers.

using System;

namespace ArmStorngNumber
{
class Program
{
    static void Main(string[] args)
    {
            int num, sum, d, i, j;
            Console.WriteLine("Armstrong Numbers between 100 to 500:");
            for (i = 100; i <= 500; i++)
            {
                j = 1;
                sum = 0;
                num = i;
                while (j <= 3)
                {
                    d = num % 10;
                    sum = sum + (d * d * d);
                    num = num / 10;
                    j++;
                }
                if (sum == i)
                {
                    Console.WriteLine(i);
                }
            }
            Console.ReadKey();
        }
    }
}


If anyone have any doubt about the program , please comment and you can also mail me on "ibsarmschauhan13@gmail.com"

Thank you so much  :)