Copy constructor for class that has member without default constructor in C++

Question

I have a class:

class Geometry{
    std::vector<Subset *> subsets;
    int verticesCount;
    ...
};

I want to add a copy constructor, so I can make a deep copy of that object (with own subsets, NOT only own pointers to same subsets).

I have tried this:

 Geometry & Geometry::operator=(const Geometry &other){
      verticesCount = other.verticesCount;
      Subset * subset = 0;
      for(unsigned int i=0; i<other.subsets.size(); i++){
           subset = new Subset();
           subsets.push_back(subset);
      }
      ...
      return *this;
 }

The problem is Subset has none default constructor, so I get error at subset = new Subset().

I also have more members that don't have default constructors.

How to solve that problem?

I would prefer NOT to add default constructors for all that members (Subset etc.) The best solution would be NOT to change member classes at all (Subset etc.), but I can add something to them, if it's necessary.

They don't have default constructors for reasons, e.g. security (I don't want to let somebody create a Model3D class without giving filename (so the vertex buffers can be created and I can assume that all Model3D objects has not-empty filename associated).

---

edit:

Because of comment. Subset is an example of member class without default constructor.

In that case it's my own class:

class Subset{
    ...
    public:
        Subset(bool useLineTopology, int vertexIndexStart, int vertexIndexAmmount = -1);
        ...
};

But I also have many others members without default constructor, like DirectX's ID3D11Buffer * constantBuffer.

Answer 1

If your Subset() class has a copy constructor then you can do as follows:

std::vector<Subset *>::const_iterator it ; // use iterators
for ( it = other.subsets.begin() ; it != other.subsets.end() ; ++it )
    subset.push_back( new Subset( *it )) ; // add a copy of original subset.

If your Subset() does not have copy constructor then you CANNOT copy.

Also, you need to remember to have ~GeometryStructure() in order to delete all Subset() objects from the subset std::vector