Question

Write a JAVA program to check whether a given number is an Armstrong number. An Armstrong number is an integer such that the sum of the cubes of its digits is equal to the number itself. For example, 371 is an Armstrong number since 3**3 + 7**3 + 1**3 = 371.

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

// CheckArmstrong.java

import java.util.Scanner;

public class CheckArmstrong {

      // method to check if a number is armstrong number

      static boolean isArmstrongNumber(int num) {

            // declaring sum of cubes to 0

            int sum = 0;

            // taking a copy of num

            int temp = num;

            // loops until temp becomes 0

            while (temp > 0) {

                  // extracting last digit

                  int digit = temp % 10;

                  // finding cube and adding to sum

                  sum += digit * digit * digit;

                  // removing last digit from temp

                  temp = temp / 10;

            }

            // at the end, if sum==num, it is an armstrong number

            if (sum == num) {

                  return true;

            }

            // else not

            return false;

      }

      public static void main(String[] args) {

            // declaring a Scanner, reading input, checking if input is an Armstrong

            // number

            Scanner scanner = new Scanner(System.in);

            System.out.println("Enter a number: ");

            int num = scanner.nextInt();

            if (isArmstrongNumber(num)) {

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

            } else {

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

            }

      }

}

/*OUTPUT (multiple run)*/

Enter a number:

371

371 is an Armstrong number

Enter a number:

123

123 is not an Armstrong number