LeetCode Reverse Integer

Reverse digits of an integer.

Example1: x = 123, return 321

Example2: x = -123, return -321

直接整数操作：

class Solution {public:int reverse(int x) {int flag = 1;if (x < 0) {flag = -1;x = -x;}int result = 0;while (x != 0) {int m = x % 10;x /= 10;result = result * 10 + m;}result *= flag;return result;}};

转字符串操作：

class Solution {public:int reverse(int x) {stringstream ss;string str;ss << x;str = ss.str();int i = 0, len = str.length() - 1;if (str[i] == '-')i++;while (i < len) {char tmp = str[i];str[i++] = str[len];str[len--] = tmp;}return atoi(str.c_str());}};