Leetcode: Count and Say

class Solution
{
public:
    //根据当前的number计算下一个number
    string countNext(string number)
    {
        string::size_type length = number.length();
        size_t count = 1;//记录相同数字的个数
        size_t index = 0;//遍历number的伪指针
        char curnum;//临时保存当前的数字
        string result;//最终结果
        //这层循环控制对number的遍历
        while (index < length)
        {
            curnum = number[index];
            //这层循环寻找相同数字并统计个数
            while (index < length)
            {
                //注意这里的index要先++然后进行比较判断，要不然会引起数组越界等问题
                if (index++ != length && curnum == number[index])
                {
                    //如果当前数字和其后的数字相等count++，统计有多少个当前数字
                    count++;
                }
                else
                {
                    //如果不相等就将count和curnum存入结果字符串中
                    result.push_back(count + '0');
                    result.push_back(curnum);
                    count = 1;
                    break;
                }
            }
        }
        return result;
    }

    string countAndSay(int n)
    {
        string number = "1";
        for (int i = 1; i < n; i++)
        {
            number = countNext(number);
        }
        return number;
    }
};