06. Barcode Generator

package examPreparation;

import java.util.Scanner;

public class P06BarcodeGenerator {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        //2345
        //6789
        int firstNum = Integer.parseInt(scanner.nextLine());
        int secondNum = Integer.parseInt(scanner.nextLine());

        //firstNum
        int digitFirstOne = firstNum / 1000;
        int digitFirstTwo = firstNum / 100 % 10;
        int digitFirstThree = firstNum / 10 % 10;
        int digitFirstFour = firstNum % 10;

        //secondNum
        int digitSecondOne = secondNum / 1000;
        int digitSecondTwo = secondNum / 100 % 10;
        int digitSecondThree = secondNum / 10 % 10;
        int digitSecondFour = secondNum % 10;

        for (int first = digitFirstOne; first <= digitSecondOne; first++) {
            for (int second = digitFirstTwo; second <= digitSecondTwo; second++) {
                for (int third = digitFirstThree; third <= digitSecondThree; third++) {
                    for (int fourth = digitFirstFour; fourth <= digitSecondFour; fourth++) {
                        boolean firstOdd = first % 2 != 0;
                        boolean secondOdd = second % 2 != 0;
                        boolean thirdOdd = third % 2 != 0;
                        boolean fourthOdd = fourth % 2 != 0;

                        if (firstOdd && secondOdd && thirdOdd && fourthOdd) {
                            System.out.printf("%d%d%d%d ", first, second, third, fourth);
                        }
                    }
                }
            }
        }
    }
}