Example: Java Program to Check Armstrong Number or Not without using Math.pow() function

// Java Program to Check Armstrong Number using Math.pow() function
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        int x, y, z, rem, rem2 = 1, n = 0, m = 0;
        double r = 0.00;
        // x - To store the input number
        // y & z - To store the storage of original input number to check
        // rem & rem2 - To store the reminder
        // r - To store the result variable

        System.out.println("-----Enter the integer number-----");
        x = in.nextInt();

        z = y = x;

        while (y != 0) {
            y /= 10;
            ++n;
        }

        m = n;

        while (z != 0) {
            rem = z % 10;

            rem2 = 1;
            while (n > 0) {
                rem2 *= rem;
                --n;
            }
            n = m;

            r += rem2;
            z /= 10;
        }

        // if x is equal to r, the number is an Armstrong number
        if ((int) r == x) {
            System.out.println("\n" + x + " is an Armstrong number.");
        } else {
            System.out.println("\n" + x + " is not an Armstrong number.");
        }
    }
}