分了4种情况，把符号前后的数分别逆转，再组合起来输出
by Zwbrother @ 2024-03-03 15:58:43
@[Zwbrother](/user/1260401) 输入可能是：`000.00089`
by Jadejunxi @ 2024-03-11 18:09:23
@[Zwbrother](/user/1260401) 不能用'\0'空字符
by Jadejunxi @ 2024-03-11 18:26:34
不能在字符串里有\0
by Jadejunxi @ 2024-03-11 18:27:09