In previous post How to reverse a number in Java we learnt how to reverse a positive or negative numbers in java

In this post we will write a java program to check Whether number is armstrong or not.

**What is Armstrong number?**

An **n-digit number** that is the sum of the th powers of its digits is called an Armstrong number.

In another words we can define Armstrong number as below:

We can define an ** Armstrong number** is a *number that is equal to the sum of the digits in a number raised to the power of number of digits in the number*.

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package com.kkjavatutorials.client; import java.util.Scanner; /** * @author KK JavaTutorials * Java program to check Armstrong number */ public class ClientTest { public static void main(String[] args) { try (Scanner scanner = new Scanner(System.in)) { // Take a number from keyboard using Scanner System.out.println("Enter Number:"); int number = scanner.nextInt(); boolean isArmstrong = isArmstrongNumber(number); if (isArmstrong) { System.out.println(number + " is an Armstrong number"); } else { System.out.println(number + " is not an Armstrong number"); } } catch (Exception e) { System.out.println("Please Enter valid number.."); e.printStackTrace(); } } private static boolean isArmstrongNumber(int number) { //convert number to String String numberToString = String.valueOf(number); int lengthOfNumber = numberToString.length(); int numberCopy = number; int sum = 0; while (numberCopy != 0) { int remainder = numberCopy % 10; //Here we use Math class pow function to get digit raised to the power total number of digits sum = sum + (int) Math.pow(remainder, lengthOfNumber); numberCopy = numberCopy / 10; } return (sum == number) ? true : false; } } |

**I have tested above program for few inputs as below. You may check for other input as well** .

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Enter Number: 153 153 is an Armstrong number Enter Number: 453 453 is not an Armstrong number Enter Number: 371 371 is an Armstrong number Enter Number: 9474 9474 is an Armstrong number Enter Number: 1 1 is an Armstrong number |

That’s all about this topic How to check Armstrong number java program

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