LeetCode7 给定一个 32 位有符号整数，将整数中的数字进行反转。

class Solution {
public:
    int reverse(int x) {
long long x1 = abs(x);
        long long y=0, n=0;
        std::vector<int> i;
        while(x1/(long long)(pow(double(10),int(n))))
        {
            i.push_back(x1%(long long)(pow(double(10),int(n+1)))/(long long)(pow(double(10),int(n))));
            ++n;
        }  
        for(int j = 0; j < i.size(); ++j)
        {
            auto d = (long long)(pow(double(10),int(i.size()-j-1)));
            auto b = (long long)(i[j]);
            y += b*d;
        }
        if(x < 0)
        {
            y = -y;
        }
        if(y < (-pow(double(2),31)) || y > (pow(double(2),31)-1))
        return 0;
        return y;
    }
};