LeetCode OJ--Valid Palindrome

http://oj.leetcode.com/problems/valid-palindrome/

判断是否为回文串

    bool isPalindrome(string s) {
        int i = ,j = s.length() -;
        int flag = ;
 
        if(s=="")
            return true;
 
        while(i<=j)
        {
            while(!('a'<= s[i] && s[i]<= 'z' || 'A' <= s[i] && s[i] <='Z' || s[i]>= ''&&s[i]<='') || s[i] == ' ' )
            {
                if(i== s.length())
                    break;
                i++;
            }
            while(!('a'<= s[j] && s[j]<= 'z' || 'A' <= s[j] && s[j] <='Z' || s[j]>= ''&&s[j]<='') || s[j] == ' ')
            {
                if(j==)
                    break;
                j--;
            }
            if(toupper(s[i]) != toupper(s[j]) && i<=j)
            {
                flag = ;
                break;
            }
            i++;
            j--;
        }
        if(flag == )
            return false;
        else
            return true;
    }