program to find armstrong number between 1 to 1000

Question

sir, 

why this code is not work i is run only for 1

 

using System;

public class Arm2

{

public static void Main()

{

int reminder, i, num;

for(i=1; i<1000; i++)

{

int sum = 0;

num = i;

while(num>0)

{

reminder = num % 10;

sum = reminder*reminder*reminder;

num = num/10;

}

if(sum == i)

{

Console.WriteLine("{0} is armstrong number.", i);

}

}

Console.ReadLine();

}

}