LeetCode Reverse Words in a String(反转字符串)

class Solution {public:    void reverseWords(string &s) {if(s=="");else{vector<string> vec;int start = 0;for(int i=0;i<s.length();i++){if(s.at(i)==' '){vec.push_back(s.substr(start,i-start));start = i+1;}else if(i == s.length()-1){vec.push_back(s.substr(start,i+1 - start));  }}std::reverse(vec.begin(),vec.end());vector<string>::iterator iter = vec.begin();s.erase();while(iter != vec.end()){s+=*iter+" ";iter++;}s.erase(s.length()-1);}cout<<s<<endl;    }};

第一次写的代码：