C++ Programming - Constructors and Destructors - Discussion

#include<iostream.h> 
class BixBase
{
    protected:
    int x, y; 
    public:
    BixBase(int xx = 0, int yy = 0)
    {
        x = xx;
        y = yy; 
    } 
    void Show()
    {
        cout<< x * this->y << endl;
    }
};
class BixDerived
{
    private:
        BixBase objBase; 
    public:
    BixDerived(int xx, int yy) : objBase(xx, yy)
    {
        objBase.Show();
    } 
    ~BixDerived()
    { }
};
int main()
{
    BixDerived objDev(10, 20); 
    return 0;
}