i need someone who explain me these lines of code part by part and i need some help in using "ostream" with simple examples. thank you :).

```
inline std::ostream& operator<<(std::ostream& os, const Telegram& t)
{
  os << "time: " << t.DispatchTime << "  Sender: " << t.Sender
     << "   Receiver: " << t.Receiver << "   Msg: " << t.Msg;

  return os;
}

```

UPDATE 1: when i use this function it doesnt compile and the error says: 

std::ostream& class::operator<<(std::ostream& os, const Telegram& t) must take exactly one argument