Armstrong number is a number which is equal to sum of digits raise to the power total number of digits in the number.

Example :

3³+ 7³ + 1³ = 371

1⁴ + 6⁴ + 3⁴ + 4⁴=1634

Below is JAVA program to check Armstrong Number.

import java.util.Scanner;

class ArmstrongNumber {
public static void main(String args[]) {
int n, sum = 0, temp, remainder, digits = 0;

Scanner in = new Scanner(System.in);
System.out.println("Input a number to check if it is an Armstrong number");
n = in.nextInt();

temp = n;

// Count number of digits

while (temp != 0) {
digits++;
temp = temp / 10;
}

temp = n;

while (temp != 0) {
remainder = temp % 10;
sum = sum + power(remainder, digits);
temp = temp / 10;
}

if (n == sum)
System.out.println(n + " is an Armstrong number.");
else
System.out.println(n + " is not an Armstrong number.");
}

static int power(int n, int r) {
int c, p = 1;

for (c = 1; c <= r; c++)
p = p * n;

return p;
}
}

More Info

For more Algorithms and Java Programing Test questions and sample code follow below links

• Frequently Asked Algorithms and Programs in Interviews
• Java Sample Code
• JDBC Sample Code