9. Palindrome Number （考虑负数的情况）

Determine whether an integer is a palindrome. Do this without extra space.

long int reverse(int x) {
    long int ret = 0;
    
    while(x>0){
        ret = ret*10 + x%10;
        x /= 10;
    }
    return ret;
}

bool isPalindrome(int x) {
    if(x<0) return false; //consider case of negative number
    if(x==reverse(x)) return true;
    else return false;
}