rajkumar-p

class FilesPurger {
public:
    virtual ~FilesPurger();
    virtual void purge(const std::string &root) = 0;
};

rajkumar-p

class DiskJanitor {
private:
    std::unique_ptr<FilesPurger> _purger;
public:
    DiskJanitor(std::unique_ptr<FilesPurger> purger);

    void clean_files(const std::string &root);
};

rajkumar-p

class TextData {
private:
    std::string _data;
    std::unique_ptr<SpellChecker> _spell_checker;
    std::unique_ptr<StorageManager> _storage_manager;
    ...
    
 public:
    int save(const std::string &loc,
             const TextData &text_data)

rajkumar-p

class StorageManager {
    virtual int save(const std::string &loc,
            const TextData &text_data) = 0;
};

class TextFileStorageManager : public StorageManager {
    int save(const std::string &loc,
             const TextData &text_data);
};

rajkumar-p

TextData text_data("Some data.",
	std::unique_ptr<SpellChecker>(new SpellChecker())
);
text_data.spell_check();
text_data.set_spell_checker(
	std::unique_ptr<SpellChecker>(new AdvancedSpellChecker())
);

text_data.spell_check();

rajkumar-p

class AdvancedSpellChecker : public SpellChecker {
    std::vector<std::string> spell_check(const std::string &data);
};

rajkumar-p

class TextData {
private:
    std::string _data;
    std::unique_ptr<SpellChecker> _spell_checker;

public:
    TextData(const std::string &s,
            std::unique_ptr<SpellChecker> sc);
    TextData(const TextData &other);
    TextData& operator=(const TextData &other);

rajkumar-p

class SpellChecker {
private:
    std::set<std::string> _dict;

public:
    SpellChecker();
    virtual ~SpellChecker();

    virtual std::vector<std::string> spell_check(const std::string &data);
};

rajkumar-p

class TextData {
private:
    std::string _data;
    
public:
    // Methods
};

rajkumar-p

std::unique_ptr<File> home(
        std::make_unique<DirectoryFile>("/users/raj", 700)
);

std::unique_ptr<File> f1(
        std::make_unique<RegularFile>("file1", 644)
);
std::unique_ptr<File> f2(
        std::make_unique<RegularFile>("file2", 644)
);