http://oj.leetcode.com/problems/reverse-integer/

Reverse Integer.java

public class Solution {
    public int reverse(int x) {
        if (x == 0) return x;
        int digit = 0;
        if (x < 0){
            digit = 1;
            x = -x;
        }
        int ret = 0;
        while (x > 0){
            int temp = x % 10;
            x = x / 10;
            ret = ret * 10 + temp;
        }
        if (digit == 1) ret = -ret;
        return ret;
    }
}