To Find out whether a number is Armstrong number

 Armstrong number is a number that is the sum of its own digits each raised to the power of the number of digits.

Let us Look at how to find out whether the number is Armstrong using java.

Note: The input is saved in Text file.

Input:

7

181

153

Output:

True

False

True

import java.io.BufferedReader;

import java.io.FileNotFoundException;

import java.io.FileReader;

import java.io.IOException;

import java.io.File;

public class Armstrong {

    public static void main (String[] args)  throws FileNotFoundException,NumberFormatException{

    

    File file = new File(args[0]);

    BufferedReader in = new BufferedReader(new FileReader(file));

   int len;

   String currentline;

                                double num;

                                int y;

                                int sum = 0;

                                char z;

   try

    { 

        while ((currentline = in.readLine()) != null) 

      {

        len=currentline.length();

        if(len>1)

                                {

                                    for(int i=0;i<currentline.length();i++)

                                                {

                                                               

                                                                z=currentline.charAt(i);

                                                                y=Character.getNumericValue(z);

                                                               

                                                                num=Math.pow(y, len);

                                                                sum+=num;

                                                               

                                                }

                                }

       else

                                {

                                                sum=Integer.parseInt(currentline);

                                }

                                if(sum==Integer.parseInt(currentline))

                                                                                                {

                                                                                                                System.out.println("True");

                                                                                                }

                                                                                                else

                                                                                                {

                                                                                                                System.out.println("False");

                                                                                                }

                                                                                                sum=0;

      }

    }catch (IOException e) {

                                               

                                                e.printStackTrace();

                                } catch(NumberFormatException e)

                                {

                                                e.printStackTrace();

                                }

  }

}