leetcode Reverse Integer 007

Reverse digits of an integer.

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

class Solution {
public:
int reverse(int x) {
const int MAXX = 0x7fffffff;
int flag = 1;
if(x < 0)
flag = -1;
x = flag*x;

int sum = 0, overflow=0;

while(x != 0) {
if(MAXX/10 < sum) overflow = 1;
if(sum < 0) overflow = 1;
sum = sum*10+x%10;
x = x/10;
}
if(overflow) return 0;

return flag*sum;
}
}