class Solution {
public:
    string reverseWords(string s) {
        stringstream ss(s);
        string temp = "";
        string res = "";
        while (ss >> temp) {
            cout<<temp<<endl;
            res.insert(0, temp + " ");
        }
        res.erase(res.end() - 1);
        return res;
    }
};

这种写法是为了熟悉stringstream、insert和erase。