反转 字符串

void reverseWords(string &s)
	{
		string rs;
		for (int i = s.length()-1; i >= 0; )
		{
			while (i >= 0 && s[i] == ' ') i--; //空格都要过滤
			if (i < 0) break;
			if (!rs.empty()) rs.push_back(' '); //不为空的时候，每个单词之间要push一个空格
			string t;
			while (i >= 0 && s[i] != ' ') t.push_back(s[i--]);
			reverse(t.begin(), t.end());
			rs.append(t); //把t接过来 
		}
		s = rs;
	}

 void main()
 {
 string str;
 str="the sky is blue  ";
 reverseWords(str);
 cout<<str<<endl;
 
 }