C++ protected access

[cosminflorea]

This code failed to compile with both gcc and Comeau online compiler - the call to f() through a A* pointer in C::g() seems to be invalid and the call with a pointer to C it is valid, but i don't understand why. Could you explain it to me, please?

class A
{
protected:
		virtual void f() {}
};

class C : public A
{
public:
		void g();
};

void C::g()
{
		A* pA = new C();  
		pA->f();			   // not accessible ?
		C* pC = new C(); 
		pC->f();			   // OK
}

int main()
{
}