虚函数缺省实参

Class Base
{
public:
    virtual void foo( int ival = 1024 )
    {
        cout << "Base::foo() -- ival: " << ival << endl;
    }
};

class Derived : public Base
{
public:
    virtual void foo( int ival = 2048 )
    {
        cout << "Derived::foo() -- ival: " << ival << endl;
    }
};

int main()
{
    Derived *pd = new Derived;
    Base *pb = pd;
    
    pb->foo();
    pd->foo();
    
    delete pd;
    pb = NULL;

    return 0;
}