Reverse Words in a String. Given an input string, reverse the string word by word. For example, Given s = "the sky is blue", return "blue is sky the".

reverseWords.cc

class Solution {
public:
    void reverseWords(string &s) {
        if(s.size() == 0)
            return;
        reverse(s.begin(), s.end());
        // reverse word by word
        istringstream iss(s);
        string word;
        ostringstream oss;
        while(iss >> word)
        {
            reverse(word.begin(), word.end());
            oss << word << ' ';
        }
        string res = oss.str();
        if(res == "")
        {
            s=res;
        }
        else
        {
            s.assign(res.begin(), res.end()-1);
        }
    }
};