leetcode 9.Palindrome Number

9. Palindrome Number
Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.

Example 1:

Input: 121
Output: true

Example 2:

Input: -121

Output: false
Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.

Example 3:

Input: 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.
Follow up:

Coud you solve it without converting the integer to a string?

class Solution {
public:
    bool isPalindrome(int x) {
        long long tmp = x;
        long long calc = 0;
        bool ret = false;
        while(x)
        {
            calc = calc * 10 + x%10;
            x = x/10;
        }
        //cout<<"calc:"<<calc<<endl;
        if(calc==tmp && tmp >=0){
            ret = true;
            //cout<<"true"<<endl;
        }
        return ret;
    }
};