StrongNumberCheck.java

// 31. Write a program to check if a given number is a strong number.

import java.util.Scanner;

public class StrongNumberCheck {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter a number: ");
        int num = scanner.nextInt();
        boolean isStrong = isStrongNumber(num);
        if (isStrong) {
            System.out.println(num + " is a strong number.");
        } else {
            System.out.println(num + " is not a strong number.");
        }
        scanner.close();
    }

    public static boolean isStrongNumber(int num) {
        int originalNum = num;
        int sum = 0;
        while (num > 0) {
            int digit = num % 10;
            sum += factorial(digit);
            num /= 10;
        }
        return sum == originalNum;
    }

    public static int factorial(int n) {
        if (n == 0 || n == 1) {
            return 1;
        }
        return n * factorial(n - 1);
    }
}