Java Program to check if Number is Armstrong or not

 Logic for Armstrong number :) 

Armstrong Number

An Armstrong number is a positive m-digit number that is equal to the sum of the m^th powers of their digits. It is also known as pluperfect, or Plus Perfect, or Narcissistic number. It is an OEIS sequence A005188. Let’s understand it through an example.

Armstrong Number Example

1: 1¹ = 1

2: 2¹ = 2

3: 3¹ = 3

153: 1³ + 5³ + 3³ = 1 + 125+ 27 = 153

125: 1³ + 2³ + 5³ = 1 + 8 + 125 = 134 (Not an Armstrong Number)

1634: 1⁴ + 6⁴ + 3⁴ + 4⁴ = 1 + 1296 + 81 + 256 = 1643

//Armstrong number list:0,1,153,370,371,407,1634

//Eg 153 rest to 3(Total number of digit ) each digit if addition come original number.

package javaPrograms;

import java.util.Scanner;

public class ArmstrongNumber {

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

System.out.println("Enter the number");

int number = sc.nextInt();

int t1=number;

int length = 0;

while(t1!=0) {

t1 = t1/10;

length = length+1;  // for find out number of digits

}

int t2 = number;

int arm = 0;

int rem ;

while(t2!=0) {

int mul =1;

rem = t2%10;

for(int i=1;i<=length;i++) {

mul = mul*rem;

}

arm = arm+mul;

t2 = t2/10;

}

if(arm==number) {

System.out.println(number +"is Armstrong number");

}

else {

System.out.println(number +"is not Armstrong number");

}

}

}