leetcode Reverse integer

题目：
Reverse digits of an integer.

Example1: x = 123, return 321
Example2: x = -123, return -321

Here are some good questions to ask before coding. Bonus points for you if you have already thought through this!

If the integer’s last digit is 0, what should the output be? ie, cases such as 10, 100.

Did you notice that the reversed integer might overflow? Assume the input is a 32-bit integer, then the reverse of 1000000003 overflows. How should you handle such cases?

For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

题目比较简单， 但是要注意一点的是要考虑判断溢出， 判断溢出的方法我是参考别人的。。。。

class Solution
{
  public:
     int reverse( int x)
     {
        const int max = 0x7fffffff;  //要考虑溢出
        const int min = 0x80000000;
        long long  res=0;
        while(x!=0)
        {
          res=res*10+x%10;
          if(res>max || res<min)
            return 0;
          x=x/10;
        }

       return res;
     }
};

判断溢出的方法是用一个long long 型来保存反转结果， 然后判断他与maxint 或 minint的 大小， 溢出则返回0。