9. Palindrome Number

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

题目含义：不要使用额外空间，判断整数是否为回文

    public boolean isPalindrome(int x) {
        int rev = 0;
        int y=x;
        while (y>0){
            rev = rev*10 + y%10;
            y = y/10;
        }
        return x==rev;      
    }