问在Java中如何在没有递归方法的情况下将给定的数归结为两位数？

EN

difference between 6 and 9 is 3
difference between 9 and 2 is 7
difference between 2 and 8 is 6

difference between 3 and 7 is 4
difference between 7 and 6 is 1

public static int twodigit(int value) {
    while (value > 99)
        value = reduce(value);
    return value;
}
private static int reduce(int value) {
    return (value<=9? 0:reduce(value/10)*10 + Math.abs(value/10%10-value%10));
}