零星笔记，待整理

  //用 getline 函数从输入读取整行内容。然后为了获得每行中的单词，将一个     //istringstream 对象与所读取的行绑定起来，这样只需要使用普通的  //string 输入操作符即可读出每行中的单词。  string line, word;// will hold a line and word from input, rectively  while (getline(cin, line))     {            // read a line from the input into line            // do per-line processing    istringstream stream(line);  // bind to stream to the line we read    while (stream >> word)    {          // read a word from line           // do per-word processing    }  }

//stringstream 对象的一个常见用法是，需要在多种数据类型之间实现自动格式化时//使用该类类型     int val1 = 512, val2 = 1024;    ostringstream format_message;    // ok: converts values to a string representation    format_message << "val1: " << val1 << "\n"                   << "val2: " << val2 << "\n";//相反，用 istringstream 读 string 对象，即可重新将数值型数据找回来   istringstream input_istring(format_message.str());   string dump; // place to dump the labels from the formatted message   input_istring >> dump >> val1 >> dump >> val2;   cout << val1 << " " << val2 << endl;  // prints 512 1024