Leetcode 38: Count and Say

// 利用递归，需要注意最后一个数不能忘了加进去1 is read off as "one 1" or 11.
11 is read off as "two 1s" or 21.
21 is read off as "one 2, then one 1" or 1211.

class Solution {
public:
    string countAndSay(int n) {
        if(n == 1)
            return "1";
        else if (n == 2)
            return "11";
        else 
        {
            string result_pre = countAndSay(n-1);
            string result = "";
            char temp = result_pre[0];
            int count_pre = 1;
            for(int i=1; i<result_pre.length();i++)
            {
                if(temp == result_pre[i])
                    count_pre++;
                else
                {
                    result = result +  char(count_pre + '0') + temp;
                    count_pre = 1;                    
                }
                temp = result_pre[i];
            }
            result = result + char(count_pre + '0') + result_pre[result_pre.length()-1];
            return result;
        }
    }
};