Design a class Message that models an e-mail message. A message has a recipient, a sender, and a message text. Support the following member functions:
- A constructor that takes the sender and recipient and sets the time stamp to the current time
- A member function append that appends a line of text to the message body
- A member function to_string that makes the message into one long string like this: "From: Harry Hacker\nTo: Rudolf Reindeer\n ..."
- A member function print that prints the message text.
Write a program that uses this class to make a message and print it.