Design Patterns - Chain of Responsibility

#include <iostream>
#include <string>
using namespace std;

class Photo 
{
public:
    Photo(string s) : mTitle(s) 
    {
	cout << "Processing " << mTitle << " ...\n";
    }

private:
    string mTitle;
};

class PhotoProcessor
{
public:
    PhotoProcessor() : mNextProcessor(0){ }

public:
    void process(Photo &p;) {
        processImplementation(p);
        if (mNextProcessor != 0) 
            mNextProcessor->process(p);
    }

    virtual ~PhotoProcessor() { }

    void setNextProcessor(PhotoProcessor *p) {
        mNextProcessor = p;
    }

protected:
    virtual void processImplementation(Photo &a;) = 0;

private:
    PhotoProcessor *mNextProcessor;
};

class Scale : public PhotoProcessor
{
public:
    enum SCALE { S50, S100, S200, S300, S500 };
    Scale(SCALE s) : mSCALE(s) { }

private:
    void processImplementation(Photo &a;) {
        cout << "Scaling photo\n";
    }

    SCALE mSCALE;
};

class RedEye : public PhotoProcessor
{
private:
    void processImplementation(Photo &a;) {
        cout << "Removing red eye\n";
    }
};

class Filter : public PhotoProcessor
{
private:
    void processImplementation(Photo &a;) {
        cout << "Applying filters\n";
    }
};

class ColorMatch : public PhotoProcessor
{
private:
    void processImplementation(Photo &a;)
    {
        cout << "Matching colors\n";
    }
};

void processPhoto(Photo &photo;)
{   
    ColorMatch match;
    RedEye eye;
    Filter filter;
    Scale scale(Scale::S200);
    scale.setNextProcessor(&eye;);
    eye.setNextProcessor(&match;);
    match.setNextProcessor(&filter;);
    scale.process(photo);
}

int main()
{
    Photo *p = new Photo("Y2013 Photo");
    processPhoto(*p);
    return 0;
}

Output:

Processing Y2013 Photo ...
Scaling photo
Removing red eye
Matching colors
Applying filters