C++ new[] into base class pointer crash on array access

Question

When I allocate a single object, this code works fine. When I try to add array syntax, it segfaults. Why is this? My goal here is to hide from the outside world the fact

Answer 1

I have figured out a workaround based on your answers. It allows me to hide the implementation specifics using a layer of indirection. It also allows me to mix and match objects in my array. Thanks!

#include 

using namespace std;

// file 1

class a
{
    public:
        virtual void m() { }
        virtual ~a() { }
};

// file 2

class b : public a
{
    int x;

    public:
        void m() { cout << "b!\n"; }
};

// file 3

class c : public a
{
    a **s;

    public:
        // PROBLEMATIC SECTION
        c() { s = new a* [10]; for(int i = 0; i < 10; i++) s[i] = new b(); }
        void m() { for(int i = 0; i < 10; i++) s[i]->m(); }
        ~c() { for(int i = 0; i < 10; i++) delete s[i]; delete[] s; }
        // END PROBLEMATIC SECTION
};

// file 4

int main(void)
{
    c o;

    o.m();

    return 0;
}