Add Peterson number in Java

Basics/PetersonNumber/PetersonNumber.java

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+package Basics.PetersonNumber;
+
+import java.util.Scanner;
+
+public class PetersonNumber {
+	/**
+	 * Peterson Number is that sum of each digit's factorial equals to number
+	 * ex) 145
+	 * 1! + 4! + 5!
+	 * 1 + 24 + 120 = 145
+	 * Peteson Number!
+	 *
+	 * @author Royce
+	 * @since 2022.02.19
+	 */
+
+	public static void main(String[] args) {
+		Scanner input = new Scanner(System.in);
+		System.out.print("Enter Number : ");
+
+		String userInput = input.nextLine();
+		try {
+			int number = Integer.parseInt(userInput);
+			checkPositive(number);
+		} catch (NumberFormatException e) {
+			System.out.println("Number must be integer more than 1");
+			return;
+		}
+
+		System.out.println(
+			isPetersonNumber(userInput)
+		);
+
+
+	}
+
+	private static void checkPositive(int number) {
+		if (number <= 0) {
+			throw new NumberFormatException();
+		}
+	}
+
+	private static String isPetersonNumber(String userInput) {
+		int userNumber = Integer.parseInt(userInput);
+		String[] digits = userInput.split("");
+		int sum = 0;
+		for (String digit : digits) {
+			sum += factorial(digit);
+		}
+
+		if (sum == userNumber) {
+			return userNumber + " is Peterson Number!";
+		}
+		return userNumber + " is not Peterson Number!";
+	}
+
+	private static int factorial(String digit) {
+		int num = Integer.parseInt(digit);
+		int ans = 1;
+		for (int i = num; i > 0; i--) {
+			ans *= i;
+		}
+		return ans;
+	}
+
+}