代码的完整性：打印1到最大的n位数

public class Main {
    public static void main(String[] args) {
        Main test = new Main();
        int n = 4;
        int[] arr = new int[n];
        test.PrintMaxOfNDigits(arr, 0);
    }

    private void PrintMaxOfNDigits(int[] arr, int index) {
        if (index == arr.length - 1) {
            for (int i = 0; i < 10; i++) {
                arr[index] = i;
                PrintNumber(arr);
            }
            return;
        }
        for (int i = 0; i < 10; i++) {
            arr[index] = i;
            PrintMaxOfNDigits(arr, index + 1);
        }

    }

    private void PrintNumber(int[] arr) {
        int i = 0;
        while (arr[i] == 0) {
            i++;
            if (i == arr.length) {
                return;
            }
        }
        for (; i < arr.length; i++) {
            System.out.print(arr[i]);
        }
        System.out.print("\t");
    }

}