c++関数オブジェクト名とポインタによる虚関数へのアクセス

#include 
using namespace std;

class base
{
public:
    virtual void disp()
    {
        cout << "hello,base" << endl;
    }
};

class child :public base {
public:
    void disp() {
        cout << "hello,child" << endl;
    }
};

int main() {

    base obj_base;
    child obj_child;
    obj_base.disp();
    obj_child.disp();

    obj_base = obj_child;
    obj_base.disp();


    obj_base.base::disp();
    obj_child.base::disp();
    obj_child.child::disp();
    system("pause");
    return 0;

}

//11-3          
#include 
using namespace std;

class base
{
public:
    virtual void disp()
    {
        cout << "hello,base" << endl;
    }
    void print()
    {
        cout << "base::print()" << std::endl;
    }
};
class child :public base {
public:
    void disp() {
        cout << "child disp()" << endl;

    }
    void print() {

        cout << "child print()" << endl;
    }
};

int main() {
    base obj_base;
    base * pBase = &obj_base;
    pBase->disp();

    //child 
    child obj_child;
    child * _pChild = &obj_child;
    _pChild->disp();

    cout << "derivide pointer to base pointer" << endl;
    pBase=_pChild;
    pBase->disp();   //         child     

    //_pChild = (child *)&pBase;
    //_pChild->disp();

    _pChild->base::disp();  //     
    system("pause");
    return 0;
}