06. Barcode Generator

package examPreparation;

import java.util.Scanner;

public class BarcodeGenerator {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int firstNumber = Integer.parseInt(scanner.nextLine());
        int secondNumber = Integer.parseInt(scanner.nextLine());

        // 2345 / 1000 => 2,345 => int = 2
        int firstDigitInFirstNumber = firstNumber / 1000;
        int firstDigitInSecondNumber = secondNumber / 1000;

        // 2345 / 100 = 23.45 => 23 % 10 = 3
        int secondDigitInFirstNumber = firstNumber / 100 % 10;
        int secondDigitInSecondNumber = secondNumber / 100 % 10;

        // 2345 / 10 = 234.5 => 234 % 10 = 4
        int thirdDigitInFirstNumber = firstNumber / 10 % 10;
        int thirdDigitInSecondNumber = secondNumber / 10 % 10;

        // 2345 % 10 = 5
        int forthDigitInFirstNumber = firstNumber % 10;
        int forthDigitInSecondNumber = secondNumber % 10;

        for (int i = firstDigitInFirstNumber; i <= firstDigitInSecondNumber; i++) {
            for (int j = secondDigitInFirstNumber; j <= secondDigitInSecondNumber; j++) {
                for (int k = thirdDigitInFirstNumber; k <= thirdDigitInSecondNumber; k++) {
                    for (int l = forthDigitInFirstNumber; l <= forthDigitInSecondNumber; l++) {

                        if (i % 2 != 0 && j % 2 != 0 && k % 2 != 0 && l % 2 != 0) {
                            System.out.printf("%d%d%d%d ", i, j, k, l);
                        }
                    }
                }
            }
        }

    }
}