2 different Java programs to check for Moran number

Java program to check if a number is a Moran number or not:

In this post, we will discuss how to check if a number is a Moran number or not. We will learn what is a Moran number and how to check if a number is Moran. The Java program will take one number as input from the user, check if the number is Moran or not and print the result.

What is a Moran number:

A number is called a Moran number if we divide the number by the sum of its digits, it returns a prime number. So, we have to calculate the sum of the digits and divide the number by this sum. If the result is a prime number, we can print that it is a Moran number. Else, it is not.

The program will take one number as input from the user and print if it is a Moran number or not.

Algorithm to check if a number is Moran:

We can use the below algorithm to check if a number is a Moran number or not:

Take the number as input from the user.
Find the sum of the digits of the number:
- Initialize one variable as 0 to hold the sum of digits of the number.
- Run one loop that will run until the value of the number becomes 0.
- On each iteration of the loop, find the last digit of the number. Add this to the sum variable.
- Remove the last digit from the number before moving to the next iteration.
- Once the loop will end, the sum variable will hold the sum of the digits of the number.
Divide the number by the sum of digits. Check if it is a prime number or not.
To check if the number is prime:
- Use a loop from i = 2 to i = number/2.
- On each iteration, check if the number is divisible by i or not.
- If yes, the number will be a prime number as it is divisible by 1 and another number that is not equal to the number itself.
- Else, the number is not a prime number.
If the result is prime, the given number is a Moran number. Else, it is not a Moran number.

Let’s use the above algorithm to write a program in Java.

Method 1: Java program to check if a number is Moran or not:

The following program checks if a number is a Moran number or not:

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        // part 1
        int number;
        Scanner scanner = new Scanner(System.in);

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

        // part 2
        int sumOfDigits = 0, lastDigit, copyNumber = number;

        while (copyNumber > 0) {
            lastDigit = copyNumber % 10;
            sumOfDigits += lastDigit;
            copyNumber = copyNumber / 10;
        }

        int divisionResult = number / sumOfDigits;

        // part 3
        boolean isPrime = true;
        for (int i = 2; i <= divisionResult / 2; i++) {
            if (divisionResult % i == 0) {
                isPrime = false;
                break;
            }
        }

        if (isPrime) {
            System.out.println(number + " is a Moran number.");
        } else {
            System.out.println(number + " is not a Moran number.");
        }

    }
}

I divided the program into three parts. In part 1,

The integer variable number is used to keep the user input number.
The Scanner variable scanner is used to read user inputs. It asks the user to enter a number and by using the scanner object, it reads the number.

In part 2,

It is finding the sum of the digits of the number.
It creates a copy of the number, copyNumber and with a while loop, it finds the sum of the digits of the number.
The last digit of the number is found by using %10.
The last digit is added to the sumOfDigits variable, which is used to store the sum of the digits of the number.
At the end of each iteration, it removes the last digit from the number by dividing the number by 10.
It divides the number by the sum of digits of the number and assigns the value to the divisionResult variable.

In part 3,

It is checking if the result, divisionResult is prime or not.
It creates one boolean variable isPrime as true.
It runs one for loop from i = 2 to i = divisionResult/2. On each iteration, it checks if it is divisible by i or not. If yes, it assigns false to the variable isPrime and breaks from the loop.
If the value of isPrime is true, it prints that the number is a Moran number. Else, it is not a Moran number.

If you run this, it will print the below output:

Enter a number: 
46
46 is not a Moran number.

Enter a number: 
45
45 is a Moran number.

Method 2: By breaking the program into different methods:

Let’s break the above program into different methods. We can use separate methods to:

Calculate the sum of the digits of the number.
To check if a number is prime or not.
To check if a number is a Moran number or not.

The method to check for the Moran number will call the other two methods.

import java.util.Scanner;

public class Main {
    private static int getSum(int number) {
        int sumOfDigits = 0, lastDigit, copyNumber = number;

        while (copyNumber > 0) {
            lastDigit = copyNumber % 10;
            sumOfDigits += lastDigit;
            copyNumber = copyNumber / 10;
        }

        return sumOfDigits;
    }

    private static boolean isPrime(int number) {
        for (int i = 2; i <= number / 2; i++) {
            if (number % i == 0) {
                return false;
            }
        }
        return true;
    }

    private static boolean isMoran(int number) {
        int sumOfDigits = getSum(number);

        int divisionResult = number / sumOfDigits;
        return isPrime(divisionResult);
    }

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

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

        if (isMoran(number)) {
            System.out.println(number + " is a Moran number.");
        } else {
            System.out.println(number + " is not a Moran number.");
        }

    }
}

Here,

The getSum method is used to find the sum of the digits of a number. It takes one number as its parameter and returns the sum.
The isPrime method checks if a number is a prime number or not. It takes one number as its parameter and returns one boolean value, true if it is a prime and false otherwise.
The isMoran method checks if a number is a Moran number or not. It also takes one number as its parameter and returns one boolean value.

It will print similar output.

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