Learn Decorator Design Pattern in Easy Steps

#include "stdafx.h"
#pragma once
#include <iostream>
#include "Kelvin.hpp"  // include the component
// Decorator needs to keep a reference to component to decorate it

//derive from Kelvin so that interface of decorator is same. This makes life easy on the client (caller) side
//this will be our base decorator class. We are adding new behavior to Kelvin thru composition
class KelvinDecorator: public Kelvin
{
public:

	virtual ~KelvinDecorator()
	{
		delete kelvinComponent;
	}

	//ctor taking in component to decorate (i.e. Kelvin) as argument.
	KelvinDecorator(Kelvin *kelvinArgument): kelvinComponent(kelvinArgument)
	{
	}

	//overload common interface from Kelvin
	virtual void MisBehave()
	{
		//just ask kelvin to misbehave!
		kelvinComponent->MisBehave();
	}

private:

	//component to decorate
	Kelvin *kelvinComponent;

	//there is no KelvinDecorator without Kelvin, so hide default ctor
	KelvinDecorator();
};

class SpacemanDecorator: public KelvinDecorator
{
public:
	virtual ~SpacemanDecorator()
	{ 
       // std::cout << "Spaceman Dtor\n";
    }

	SpacemanDecorator (Kelvin *kelvin): KelvinDecorator(kelvin)
	{
	}

	virtual void MisBehave()
	{
		// call previous decorator
		KelvinDecorator::MisBehave();
		
		//now add this decorator's additional functionality
		std::cout<< "The fearless Spaceman Kpiff battles with the Zork!!!\n";
	}

private:
	SpacemanDecorator();
};

class DinoDecorator: public KelvinDecorator
{
public:
	virtual ~DinoDecorator()
	{ 
      //  std::cout << "Dino Dtor\n";
    }

	DinoDecorator (Kelvin *kelvin): KelvinDecorator(kelvin)
	{
	}

	virtual void MisBehave()
	{
		// call previous decorator
		KelvinDecorator::MisBehave();
		
		//now add this decorator's additional functionality
		std::cout<< "Kelvin the terrible T-Rex runs rampant in Jurassic park!\n";
	}

private:
	DinoDecorator();
};

class TracerBazookaDecorator: public KelvinDecorator
{
public:
	virtual ~TracerBazookaDecorator()
	{ 
        //std::cout << "Tracer Dtor\n";
    }

	TracerBazookaDecorator (Kelvin *kelvin): KelvinDecorator(kelvin)
	{
	}

	virtual void MisBehave()
	{
		// call previous decorator
		KelvinDecorator::MisBehave();
		
		//now add this decorator's additional functionality
		std::cout<< "TracerBazooka: Here's looking at you kid.\n";
	}

private:
	TracerBazookaDecorator();
};