virtual inheritance question

For the following classes, why is the output 1 instead of 10?:

class Top
{
public:
Top():a(1){}
Top(int arg):a(arg){}
virtual ~Top(){}
int a;
};

class Left : virtual public Top
{
public:
Left():b(2){}
int b;
};

class Right : virtual public Top
{
public:
Right(): c(3), Top(10){}
int c;
};

class Bottom : public Left, public Right
{
public:
Bottom():d(4){}
int d;
};

int main()
{
Bottom* bottom = new Bottom();
Right *right = bottom;
cout << "right->a: " << right->a << endl;

return 0;
}

re: virtual inheritance question

chrolson@gmail.com wrote:....
The virtual base class constructor must be called
from the most derived constructor. In this case it must
be called from Bottom.

John.

re: virtual inheritance question

John Grabner wrote:I know this is a bit of a digression from the OP's question but
shouldn't there be a delete Bottom; to avoid a memory leak? (I'm not
completely sure -- this is a genuine question, not a rhetorical one.)

Paul Epstein

re: virtual inheritance question

pauldepstein@att.net wrote:In my opinion, yes and no. Yes, the memory needs to be deleted, but no,
not by delete. Here would be my main:

int main()
{
boost::shared_ptr<Rightright(boost::shared_ptr<Bot tom>(new
Bottom()));
cout << "right->a: " << right->a << endl;

return 0;
}

The shared_ptr cleans up for you when it goes out of scope.

Todd Gardner

re: virtual inheritance question

The virtual base class constructor must be calledSo what happens to the explicit call to Top(10) in the initializer list
of class Right? Does it get called at all?