C++ getline函数切割字符串

class Solution {
public:
    string simplifyPath(string path) {
        stringstream is(path);
        vector<string> strs;
        string res = "", tmp = "";
        while(getline(is, tmp, '/')) {
            cout << tmp << endl;
            if(tmp == "" || tmp == ".")
                continue;
            else if(tmp == ".." && !strs.empty())
                strs.pop_back();
            else if(tmp != "..")
                strs.push_back(tmp);
        }
        for(string str:strs) 
            res +=  "/" + str;
        if(res.empty())
            return "/";
        return res;
    }
};