Mailbox

[spitfire]

Hello everyone, and I'm glad I found this forum. I am stuck in a bind and don't know where to go from here. I have a message class and a mailbox class. I need to be able to add messages into a virtual "mailbox" (mailbox.cpp), I have 75% of everything done, I just dont know how to implement a few of the remaining functions in the mailbox class, as seen below. I am a beginner at C++ and I'm sure if someone can help me get going, I can finish the rest. Thank you guys for the help, this is what I have written thus far:

//main
#include <iostream>
#include <string>
#include "message.h"
#include "mailbox.h"
using namespace std;

int main()
{
    message create("Fee","Fi");
    create.append("This is a message...");
   	create.print();

   	mailbox box;
   	box.add_message(create);
}

//message.cpp
#include <iostream>
#include <string>
using namespace std;
#include "message.h"
#include "mailbox.h"

message::message(string r, string s)
{
   recipient = r;
   sender = s;

}

void message::append(string t)
{
    text = text + t + "\n";
}

string message::to_string() const
{
   return "From: " + sender + "\n" +
      "To: " + recipient + "\n" + text;
}

void message::print() const
{
   cout << to_string();
}

//message.h
#include <iostream>
#include <string>

using namespace std;
#ifndef MESSAGE_H_
#define MESSAGE_H_

class message {
public:
   message();
   message now();
   message(string r, string s);
   void append(string t);
   string to_string() const;
   void print() const;

private:
   string sender;
   string recipient;
   string text;
};

#endif /* MESSAGE_H_ */ 

//mailbox.cpp
#include <iostream>
#include <string>
#include "message.h"
#include "mailbox.h"
using namespace std;

mailbox::mailbox()
{
	box="";
	number=0;
}

void mailbox::add_message(message m)
{
	number++;
	box=box+m.to_string();

}

void mailbox::remove_message(int i)
{

}

string mailbox::get_message(int i)const
{

}

mailbox::~mailbox() {
	// TODO Auto-generated destructor stub
}

//mailbox.h
#ifndef MAILBOX_H_
#define MAILBOX_H_
#include <iostream>
#include <string>
using namespace std;
class mailbox
{
public:
	mailbox();
	void add_message(message m);
	string get_message(int i)const;
	void remove_message(int i);
	int number;
	string box;
	virtual ~mailbox();
};

#endif /* MAILBOX_H_ */ 

[kbw]

What's missing?

mailbox's member data is public. You may want to consider making it private.

mailbox's destructor probably doesn't need to be virtual.

[spitfire]

In the mailbox.cpp class, I got started under the add_message (message m), but thats as far as I know what to do. I need to finish the remove_message and get_message functions as well. OK, I can change the member data for mailbox, I see what you're saying about that.

[kbw]

I'd expect mailbox to hold a collection of messages. So you need some kind of container in which to store messages.

Your mailbox interface has method string get_message(int i). What is i? Shouldn't it return a message and not a string?

[PanGalactic]

You probably want to use a container such as std::list to store your messages in, rather than using a single string.

[spitfire]

For now, all the messages will be packed together into one long string,which is the concatenation of all messages, since we don't yet know how to store a collection of message objects. You can tell where a new message starts by searching for a 'From:' at the beginning of a line. Thats correct, it should be message mailbox::get_message(int i) const;

[kbw]

I see. Are you able to do that? You've described it clearly, coding it should be straightforward from here.

[spitfire]

That's where I run into trouble. I dont know how to tie in the message class with the mailbox class. I just mentally don't know how I would retrieve the message from the mailbox.

[kbw]

I take it that box is the string of messages right? add_message might look like:

void mailbox::add_message(message m)
{
    box += m.to_string();
}

[spitfire]

Alright, I got that much. I need to add a number to the message so when I remove and get the message, it will know which message to get. So how will I implement that? I have a feeling its like:

void mailbox::add_message(message m)
{
    box += number+m.to_string();
}

but I can't get it to work. Any suggestions as to where to go?

[kbw]

You need to count them each time I'm afraid.

All this would be trivial if you were allowed to store them in an array of string (std::vector<std::string>).

[spitfire]

I asked about it and I am allowed to use an array. Solved the problem easily that way. Thanks for the help and support along the way!

[PanGalactic]

If arrays are allowed, then certainly vector is allowed.

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