Armstrong number in Java using for loop

Sep 06, 2019 Examples, Loops, Problem Solving, Snippet comments

It is a very good exercise to improve our logic and we wish to solve some problems. And so in this post we try to give example on how to solve this problem, determining Armstrong number in Java using for loop.

Determining Armstrong number in Java using for loop

A number is an Armstrong number if it's value is equal to the sum of cubes of its digits. Below is a solution for this using for loop:

/**
 * An example program that Determining Armstrong number in Java using for loop.
 */
public class ExampleProgram {
    public static void main(String[] args) {
        System.out.println(1 + " is armstrong? " + isArmstrongNumber(1));
        System.out.println(2 + " is armstrong? " + isArmstrongNumber(2));
        System.out.println(3 + " is armstrong? " + isArmstrongNumber(3));
        System.out.println(152 + " is armstrong? " + isArmstrongNumber(152));
        System.out.println(153 + " is armstrong? " + isArmstrongNumber(153));
        System.out.println(154 + " is armstrong? " + isArmstrongNumber(154));
    }
    public static boolean isArmstrongNumber(int number) {
        int sum = 0;
        int n = number;
        for (; n>0; ) {
            // get the last digit
            int digit = n%10;
            // cube me please and sum
            sum = sum + (digit * digit * digit);
            // and remove the digit we processed.
            n = n / 10;
        }
        return number == sum;
    }
}

And we get below output when we run the code above:

1 is armstrong? true
2 is armstrong? false
3 is armstrong? false
152 is armstrong? false
153 is armstrong? true
154 is armstrong? false