LeetCode Reverse Words in a String

class Solution {
public:
    void reverseWords(string &s) {
        string tmp;
        for(int i = s.size() - 1; i >= 0; ) {
            while(i >= 0 && s[i] == ' ') --i;
            if(i < 0) break;
            if(!tmp.empty()) tmp.push_back(' ');
            string t;
            while(i >= 0 && s[i] != ' ') {
                t.push_back(s[i--]);
            }
            reverse(t.begin(), t.end());
            tmp.append(t);
        }
        s = tmp;
        return;
    }
};