Plz help me in this example

import java.util.*;

public class calcarms

{

public static void main(String [] args)

{

 Scanner input = new Scanner(System.in);

 //Declare Variable

 int num;

 //Initialize num to 0

 num = 0;

 //Print heading

 System.out.println("Armstrong Numbers\t\tDifference between Successive Armstrong Numbers");

 //Call Armstrong method

 boolean result = Armstrong(num);  

}

public static boolean Armstrong(int num)

{

 int nums;

 //Initialize old_Arms and new_Arms to 0

 int old_Arms =0; int new_Arms = 0;

 for(int i = 0;i<=500;i++) //Iterate from 0 to 500

 {

 nums = i;

 int temp,calc = 0;

 temp = nums;  

 //Check individual digit of each number

 while(nums > 0)

 {

 int a=nums%10;  

 nums/=10;

 calc+=(a*a*a);//Find cube of number

 }

 if(temp == calc) //Check if number is armstrong

 {

 new_Arms = calc;

 old_Arms = new_Arms - old_Arms;

 System.out.println(calc+"\t\t\t"+old_Arms);//Print

 old_Arms = calc;      

 }

 }

 return true;  

};

}

Explanation:

Comments are used to explain difficult lines

answer: b

explanation: