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

class Image
{
public:
    Image(){}
    virtual ~Image(){}
    virtual void display() = 0;
};

class RealImage : public Image
{
public:
    RealImage(string fileName) : fileName(fileName)
    {
        loadFromDisk(fileName);
    }
    void loadFromDisk(string fileName)
    {
        cout << "Loading " + fileName << endl;
    }
    void display()
    {
        cout << "Displaying " + fileName << endl;
    }

private:
    string fileName;
};

class ProxyImage : public Image
{
public:
    ProxyImage(string fileName) : fileName(fileName)
    {
        realImage = nullptr;
    }
    void display()
    {
        if (realImage == nullptr)
        {
            realImage = new RealImage(fileName);
        }
        realImage->display();
    }

private:
    RealImage *realImage;
    string fileName;
};