Invoking the copy constructor of a base class for boost pointer containers?

For the below code, when v is copied, the members of Model class do not get copied.

#include <boost/ptr_container/ptr_vector.hpp>
#include <iostream>
using namespace std;

    class SomeNewClass
    {
    public:
       int a;
    };

    class Model
    {
    public:
       int i;
       SomeNewClass* s;//A deep copy won't happen here automatically

       Model() {}
       Model(const Model& m):i(m.i)
       {
        cout<<"Model Copy ctor invoked"<<endl;
       }
    };

    class ModelInherit : public Model
    {
    public:
       int j;

       ModelInherit() {}
       ModelInherit(const ModelInherit& m):j(m.j)
       {
          //i=m.i;//I don't want to copy like this. I want the copy ctor of Model to be invoked
          cout<<"ModelInherit Copy ctor invoked"<<endl;
       }
    };

    int main()
    {
       boost::ptr_vector<ModelInherit> v;
       v.push_back(new ModelInherit);
       v[0].j = 10;
       v[0].i = 20;
       v[0].s = new SomeNewClass();
       v[0].s->a = 99;

       boost::ptr_vector<ModelInherit> v2( v );
       cout<< v2[0].j <<endl;
       cout<< v2[0].i <<endl;
       //cout<< v2[0].s->a <<endl;//segmentation fault
    }

What is important to note is that if you comment out the copy constructor of ModelInherit, then the pointer container automatically copies t开发者_开发技巧he i variable in the Model class. Sad part is that "SomeNewClass* s" does not get copied. No deep copy.

So my questions are:

• Do you know how to invoke the copy constructor of the Model class in the above code?
• How do I ensure a deep copy when the pointer container is automatically copying variables so that even the 'a' variable of SomeNewClass gets copied?

---

(1) To invoke Model copy constructor, change your ModelInherit copy constructor like following:

ModelInherit(const ModelInherit& m): Model(m), j(m.j) {}

(2) Deep copy can be done like this:

Model(const Model& m): i(m.i), s(0)
{
  if(m.s != 0)
    this->s = new SomeNewClass(*(m.s));
  cout<<"Model Copy ctor invoked"<<endl;
}

And declare a copy constructor for SomeNewClass like below:

SomeNewClass(const SomeNewClass &copy) : a(copy.a)
{
  cout<<"SomeNewClass Copy ctor invoked"<<endl;
}

Don't forget to free Model::s in destructor, otherwise it will leak memory:

~Model () { delete this->s; }  // it's ok if s = 0

---

Invoking base class copy-constructor is easy:

ModelInherit(const ModelInherit& m): Model(m), j(m.j) {}
                                  //^^^^^^^^ note this

Model(m) invokes base class copy-constructor; the parameter m implicitly converts into base class.

In the base class copy-constructor, you've to manually deep-copy m.s.