Question

Provide the definition of class Message, which models an email message, in a file named Message.hpp and implement all the required member functions (see below) in a file named Message.cpp.

A message contains a header and a body, which are separated by the first full line break in the message. The message header has a sender, a recipient, a subject representing the message heading, a Unix timestamp representing the sending time of the message, a character encoding, which you can safely assume is UTF-8, and a message identification number. The message body is the message text. The Message class supports the following member functions:

(a) A constructor that takes the sender and recipient and sets the timestamp to the current time.

(b) A member function append that takes a string as an argument, appends the string to message body, and returns nothing.

(c) A member function toString that takes no arguments, makes the message into one long string (see below for an example) and returns it.

From: Minerva McGonagall\nTo:Mr. H. Potter\n\nDear Harry...

(d) A member function print that takes no arguments and prints the message text.

Answer 1

// Message.hpp

#ifndef MESSAGE_HPP_

#define MESSAGE_HPP_

#include <iostream>

#include <ctime>

using namespace std;

class Message

{

       string sender;

       string recipient;

       string subject ;

       time_t timestamp;

       string character_encoding;

       long int identification_number;

       string text;

       static long int count;

public:

       Message(string sender, string recipient);

       void append(string txt);

       string toString();

       void print();

       void setSubject(string subject);

};

#endif /* MESSAGE_HPP_ */

//end of Message.hpp

// Message.cpp

#include "Message.hpp"

#include <string>

long int Message::count = 0;

// constructor to set the sender, recipient and timestamp

Message::Message(string sender, string recipient)

{

       this->sender = sender;

       this->recipient = recipient;

       timestamp = time(NULL); // returns unix epoch time

       character_encoding = "UTF-8";

       count++;

       identification_number = count;

       subject = "";

       text = "";

}

// function to append message to message text

void Message:: append(string txt)

{

       text += txt;

}

// function to set the subject of the message

void Message::setSubject(string subject)

{

       this->subject = subject;

}

// function to return the string representation of the message

string Message:: toString()

{

       string messageStr = "From : "+sender+"\n";

       messageStr += "To : ";

       messageStr += recipient.substr(0,1)+". "+recipient.substr(recipient.find(' ')+1);

       messageStr += "\n\n";

       messageStr += "Dear "+recipient.substr(0,recipient.find(' '))+",\n";

       messageStr += text;

       return messageStr;

}

// function to print the message text

void Message::print()

{

       cout<<text;

}

//end of Message.cpp

// main.cpp : C++ program to test the message class

#include "Message.hpp"

#include <iostream>

using namespace std;

int main()

{

       Message m("Minerva McGonagall","Harry Potter");

       m.setSubject("Hi");

       m.append("How are you?\nI am good");

       cout<<m.toString();

}

//end of program

Output: