Use the observer design pattern.

Get them to work in Visual Studio or GCC $$

$*$ Add additional properties to Customer if necessary

$*$ Add additional code to the existing observers to show their functionalities, use the Customer reference to get information about the customer

$*$ Add a third type of "observer" to the project for the Customer

$*$ Prove that this new "observer" is working $($by adding outputs$)$

Your code should include outputs during object Constructor runs. Make changes to the Customer's properties and try notifying the observers. WelcomeLetter.h

#pragma once

#include "Observer.h$"$

#include "Customer.h$"$

class WelcomeLetter : public Observer

$\{$

public:

WelcomeLetter$($void$)$;

void update$($ Customer $*$myCust$)$;

public:

~WelcomeLetter$($void$)$;

$\}$;AddrVerification.cc

include "AddrVerification.h$"$

#include

using namespace std;

AddrVerification::AddrVerification$($void$)$

$\{$

$\}$

AddrVerification::~AddrVerification$($void$)$

$\{$

$\}$

void AddrVerification::update $($ Customer $*$myCust$)$

$\{$

$//$ do Address verification stuff here

$//$ can get more information about customer

$//$ in question by using myCust

cout$<<"$in AddrVerification update"$<$

using namespace std;

Customer::Customer$($void$)$

$\{$

$\}$

Customer::~Customer$($void$)$

$\{$

$\}$

void Customer::attach$($ Observer $*$myObserver$)$

$\{$

myObs.push$\_$back$($ myObserver$)$;

$\}$

void Customer::detach$($ Observer $*$myObserver$)$

$\{$

for $($int i$=0$; i$<$ myObs.size$()$; i$++)$

$\{$

if $($myObs$[$i$]==$ myObserver$)$

$\{$

myObs.erase$($myObs$.$begin$()+$i$)$;

return;

$\}$

$\}$

$\}$

void Customer::notifyObs$()$

$\{$

$//$ set arg to something that helps

$//$ tell the Observers what happened

for $($int i$=0$; i$<$ myObs.size$()$; i$++)$

$\{$

myObs$[$i$]->$update$($this$)$;

$\}$

$\}$

string$*$ Customer::getState$()$

$\{$

string $*$state$=$ new string;

$//$ set state

return $0$l;

$\}$

Customer.h

#pragma once

#include

#include

#include

#include "Observer.h$"$

using namespace std;

class Customer

$\{$

public:

Customer$($void$)$;

void attach$($ Observer $*$myObserver$)$;

void detach$($ Observer $*$myObserver$)$;

string$*$ getState$()$;

void notifyObs$()$;

private:

vector myObs;

public:

~Customer$($void$)$;

$\}$;

CustomerTest.cc

#include "Observer.h$"$

#include "Customer.h$"$

#include "AddrVerification.h$"$

#include "WelcomeLetter.h$"$

#include

int main$()$

$\{$

Customer $*$customer $=$ new Customer$()$;

WelcomeLetter $*$wl $=$ new WelcomeLetter$()$;

AddrVerification $*$av $=$ new AddrVerification$()$;

customer$->$attach$($wl$)$;

customer$->$attach$($av$)$;

customer$->$notifyObs$()$;

cin.get$()$;

$\}$

Observer.cc

#include "Observer.h$"$

Observer::Observer$($void$)$

$\{$

$\}$

Observer::~Observer$($void$)$

$\{$

$\}$

Observer.h

#pragma once

class Customer;

class Observer

$\{$

public:

Observer$($void$)$;

virtual void update$($ Customer $*$myCust$)=0$;

public:

~Observer$($void$)$;

$\}$;

WelcomeLetter.cc

#include "WelcomeLetter.h$"$

#include

using namespace std;

WelcomeLetter::WelcomeLetter$($void$)$

$\{$

$\}$

WelcomeLetter::~WelcomeLetter$($void$)$

$\{$

$\}$

void WelcomeLetter::update$($ Customer $*$myCust$)$

$\{$

$//$ do Welcome Letter stuff

$//$ here can get more

$//$ information about customer

$//$ in question by using myCust

cout$<<"$in welcome letter update"$<$ endl WelcomeLetter.h

#pragma once

#include "Observer.h$"$

#include "Customer.h$"$

class WelcomeLetter : public Observer

$\{$

public:

WelcomeLetter$($void$)$;

void update$($ Customer $*$myCust$)$;

public:

~WelcomeLetter$($void$)$;

$\}$;