Simple Ressource Manager : C++

#include <iostream>
#include <unordered_map>

static size_t indexAsset = 0;

struct Image
{
    int _w;
    int _h;
};


struct Asset
{
    int _id = 0;
    std::string _name;

    Asset()
    {
        _id = indexAsset;
        ++indexAsset;
    }

    ~Asset()
    {
        std::cout << "- Delete Asset : "<< _name << "\n";
    }

};

struct Bitmap : public Asset
{
    Image *_data = nullptr;

    Bitmap(std::string name, int w, int h)
    {
        _name = name;
        _data = new Image{w,h};
    }
    ~Bitmap()
    {
        if (_data != nullptr)
            delete _data;
    }

    Image *getData()
    {
        return _data;
    }
};

struct Font : public Asset
{
    Font(std::string name)
    {
        _name = name;
    }
    ~Font()
    {

    }
};

struct AssetManager
{
    std::unordered_map<std::string, Asset*> _mapAsset;

    ~AssetManager()
    {
        if (!_mapAsset.empty())
        {
            auto it = _mapAsset.begin();

            while (it != _mapAsset.end())
            {
                if (it->second != nullptr)
                {

                    delete it->second;
                    it->second = nullptr;
                    //it = _mapAsset.erase(it);
                }

                ++it;
            }

            _mapAsset.clear();
        }

    }

    void add(Asset *content)
    {
        _mapAsset.insert(std::pair<std::string, Asset*>(content->_name, content) );
    }

    bool del(std::string name)
    {
        auto it = _mapAsset.find(name);

        if (it == _mapAsset.end())
        {
            std::cout << "Not found : "<< name << "\n";
            return false;
        }

        if (it->second != nullptr)
        {
            delete it->second;
            it->second = nullptr;
        }

        _mapAsset.erase(it);
        //std::cout << "item found : "<< name << "\n";
        return true;

    }


    template <class C>
    C *get(std::string name)
    {
        auto it = _mapAsset.find(name);

        if (it != _mapAsset.end())
            return static_cast<C*>(it->second);

        return nullptr;
    }

    void showAll()
    {
        auto it = _mapAsset.begin();

        while (it != _mapAsset.end())
        {
            if ((*it).second != nullptr)
                std::cout << "[ "<< it->second->_name << " id = " << it->second->_id << " ]\n";

            ++it;
        }
    }

};



int main()
{

    AssetManager _assetBank;


    _assetBank.add(new Bitmap("Mugen", 640, 360));
    _assetBank.add(new Font("mainFont"));
    _assetBank.add(new Bitmap("Silver", 480, 160));

    _assetBank.showAll();

    Bitmap *myImage = nullptr;


    myImage = _assetBank.get<Bitmap>("Mugen");

    std::cout << myImage->_data->_w << "\n";


    Font *myFont = _assetBank.get<Font>("mainFont");

    std::cout << "myFont name = " << myFont->_name << "\n";

    _assetBank.del("Silver");

    _assetBank.showAll();


//    if (myImage)
//        delete myImage;

    return 0;
}