写出一个4位数，把它整理一下，其办法是：把这个数的各位数字按大到小顺序重新排列，结果不为6174；将这个数组合成最大数和一个最小数，用最大数减去最小数，最后结果为6174；否则继续 重复上面步骤；最后输出重复了几次！-Write a 4-digit, sort it, and its approach is: you put this figure at large to the small number rearrange the order, the result is not 6174