#include <boost/ptr_container/ptr_list.hpp>
#include <iostream>

using namespace std;

class BASE
{
    public:
        virtual int print() const = 0;
};

class CHILD : public BASE
{
    public:
        CHILD(int a) :
            i(a)
        {
        }
        int i;

        virtual int print() const
        {
            return i;
        }
};

int main()
{
    // good
//    boost::ptr_list<BASE> intList;
//    boost::ptr_list<BASE>::iterator iterIntList;
    // bad
    boost::ptr_list<const BASE> intList;
    boost::ptr_list<const BASE>::iterator iterIntList;


    BASE *a = new CHILD(1);
    BASE *b = new CHILD(2);
    BASE *c = new CHILD(3);


    intList.push_back(a);
    intList.push_back(b);
    intList.push_back(c);

    for (iterIntList = intList.begin(); iterIntList != intList.end(); iterIntList++)
    {
        cout << iterIntList->print() << endl;
    }

    intList.clear(); // All pointers held in list are deleted.

}