C++ Programming - Constructors and Destructors - Discussion

#include<iostream.h> 
class BixBase
{
    public:
    int x, y;
    BixBase(int xx = 0, int yy = 5)
    {
        x = ++xx; 
        y = --yy;
    }
    void Display()
    {
        cout<< --y;
    } 
    ~BixBase(){} 
};
class BixDerived : public BixBase
{
    public:
    void Increment()
    {
        y++;
    }
    void Display()
    {
        cout<< --y;
    } 
}; 
int main()
{
    BixDerived objBix;
    objBix.Increment();
    objBix.Display();
    return 0; 
}