leetcode 151. Reverse Words in a String

 1 void reverseWords(string &s)
 2     {
 3         string sret;
 4         int i = s.length() - 1;
 5         
 6         while (i >= 0)
 7         {
 8             while (i >= 0 && s[i] == ‘ ‘) 
 9                 i--;
10             if (i < 0) 
11                 break;
12             if (!sret.empty()) 
13                 sret.push_back(‘ ‘);
14 
15             string stmp;
16             while (i >= 0 && s[i] != ‘ ‘) 
17             {    
18                 stmp.push_back(s[i]);
19                 i--;
20             }
21             reverse(stmp.begin(), stmp.end());
22             sret.append(stmp);
23         }
24         s = sret;
25     }