Answer to Question #227341 in Java | JSP | JSF for zooz

Question

Write a program to print out all Armstrong numbers between a range of numbers entered by user. The following is a sample of output:

Sample 1

enter the range of numbers :10 100

the Armstrong numbers are:

No Armstrong Numbers found:

sample 2

enter the range of numbers : 100 2000

the Armstrong Numbers are :

153

370

371

407

1634

Answer 1

import java.util.Scanner;


public class ArmstrongNumbers {
	private static int power(int number, long e) {
		if (e == 0) {
			return 1;
		}
			
		if (e % 2 == 0) {
			return power(number, e / 2) * power(number, e / 2);
		}
		return number * power(number, e / 2) * power(number, e / 2);
	}


	
	private static int calculateOrderNumber(int number) {
		int counter = 0;
		while (number != 0) {
			counter++;
			number = number / 10;
		}
		return counter;
	}


	private static boolean isArmstrong(int number) {
		int n = calculateOrderNumber(number);
		int tempNumber = number, sum = 0;
		while (tempNumber != 0) {
			int r = tempNumber % 10;
			sum = sum + power(r, n);
			tempNumber = tempNumber / 10;
		}
		return (sum == number);
	}


	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		System.out.print("enter the range of numbers: ");
		int startnumber = input.nextInt();
		int endnumber = input.nextInt();
		System.out.println("the Armstrong numbers are:");
		int counter = 0;
		for (int number = startnumber; number <= endnumber; number++) {
			if (isArmstrong(number)) {
				System.out.println(number);
				counter++;
			}
		}
		if (counter == 0) {
			System.out.println("No Armstrong Numbers found:");
		}
		input.close();


	}


}