virtual-function.cpp

class CBase
{
public:
	virtual void Print() = 0; // pure virtual, abstract
};

class CDerived0 : public CBase
{
public:
	CDerived0() { puts("new0"); }
	CDerived0(const CDerived0 &) { puts("copy0"); }
	virtual void Print() override { puts("0"); }
};

class CDerived1 : public CDerived0
{
public:
	virtual void Print() override { puts("1"); }
};

void PolymorphTest()
{
	CDerived0 &r1 = CDerived1();
	r1.Print(); // 1

	CDerived1 *pInst = new CDerived1();
	(*((CDerived0 *)pInst)).Print(); // 1
	((CDerived0)*pInst).Print();     // 0 (copy0)
	pInst->CDerived0::Print();       // 0
}