C++ Programming - Functions - Discussion

#include<iostream.h> 
class Base
{
    int x, y; 
    public:
    Base() 
    {
        x = y = 0; 
    } 
    Base(int xx)
    {
        x = xx;
    }
    Base(int p, int q = 10)
    {
        x = p + q;
        y = q; 
    } 
    void Display(void)
    {
        cout<< x << " " << y << endl;
    } 
}objDefault(1, 1);

class Derived: public Base
{
    Base obj; 
    public:
    Derived(int xx, int yy): Base(xx, xx + 1)
    { }
    Derived(Base objB = objDefault)
    { } 
}; 
int main()
{
    Derived objD(5, 3);
    Derived *ptrD = new Derived(objD);
    ptrD->Display();
    delete ptrD;
    return 0; 
}