E-mail files, part III: Replying

The task

1. Ask the user for the name of an e-mail file.
2. Print a numbered list of messages contained in the e-mail file, showing sender and subject. The info for each message should be on one line.
3. Give the user the chance to read a message or reply to a message.
4. Do what the user chose.
5. Go back to step 2.

Here's an example session with the finished program:

	What is the name of the mailbox? tempMailbox

	1 aqudu@ungulates.com  Re: toys
	2 dmusican@mathcs.carleton.edu  [Bowling] Sub tonite?
	3 asdf@carleton.edu  Re: images in classes
	4 fleen@carleton.edu   Re: assignment

	View message (m) or reply (r)? m
	
	Which message do you want to view? 1

	Return-Path: 
	Received: from caesar.acns.carleton.edu (Caesar.ACNS.Carleton.edu [137.22.1.26])
	by mathcs.carleton.edu (8.9.3/8.9.3) with ESMTP id KAA15967
	for ; Wed, 24 Jan 2001 10:23:04 -0600
	Received: from mail.ungulates.com ([208.42.17.1])
	 by carleton.edu (PMDF V5.2-32 #36754)
	 with SMTP id <0G7O0039RANI9S@carleton.edu> for jondich@mathcs.carleton.edu
	 (ORCPT rfc822;jondich@carleton.edu); Wed, 24 Jan 2001 09:21:19 -0600 (CST)
	Received: from RBDOMAIN-Message_Server by mail.ungulates.com	with
	Novell_GroupWise; Wed, 24 Jan 2001 09:22:22 -0600
	Date: Wed, 24 Jan 2001 09:22:06 -0600
	From: Andrew Qudu 
	Subject: Re: toys
	To: jondich@carleton.edu
	Message-id: 
	MIME-version: 1.0
	X-Mailer: Novell GroupWise 5.5.2
	Content-type: text/plain; charset=US-ASCII
	Content-disposition: inline
	Content-Transfer-Encoding: 8bit
	X-MIME-Autoconverted: from quoted-printable to 8bit by mathcs.carleton.edu id KAA15967

	Fortunately, Talia has not noticed the missing airplane yet.
	Maybe you could mail it to us?


	1 aqudu@ungulates.com  Re: toys
	2 dmoosica@mathcs.carleton.edu  [Bowling] Sub tonite?
	3 asdf@carleton.edu  Re: images in classes
	4 fleen@carleton.edu   Re: assignment

	View message (m) or reply (r)? r

	To which message would you like to reply? 1

	[Type your message.  To end the message, type a line
	consisting of only a period.]

	Andy,

	We'll mail it to you once we're done playing with it.

	Jeff
	.
	
	[Message sent.]

Ideas

• To print the one-line message summary, you will need to extract the sender's e-mail address from the "From:" line and the subject from the "Subject:" line of each message. You can do this using a combination of the substr and find functions that go with the string type. See substr.cpp for an example of how to use them.

• Get the one-line message summary part of the program done first. It's the easier part.

• To assemble the reply message, you'll want to use a loop like this:

  
  	while( getline(inputFile,s)  &&  s != "." )
  	{
  		// Sorry--you'll need to figure out this part
  		// yourself.
  	}
  

• Once you have the reply message assembled into a string, put it into a file, like this:

  
  	string	reply;
  
  	// ... in here, assemble the reply.  See previous item.
  
  
  	// Now put the reply into a file
  
  	ofstream	outputFile( "tempFile.txt" );
  	if( !outputFile.is_open() )
  	{
  		cout << "Can't open tempFile.txt.  I'm outta here." << endl;
  		exit( 1 );
  	}
  
  	outputFile << reply;
  
  	outputFile.close();
  

• Finally, use the system() function (see system.cpp) to execute the following UNIX commands:

  
  	mail destinationaddressgoeshere < tempFile.txt
  	rm tempFile.txt
  

Have fun, start early, and keep in touch.