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cpp virtual example and tutorials

//----------------------------------------------------------------------
// Listing 9.1. Misusing the typeid() operator.
//----------------------------------------------------------------------

#include <iostream.h>
#include <typeinfo.h>

class MWindow
{
public:
    MWindow(){};
    virtual ~MWindow(){};

    void show(){}; //non-virtual
    //...
};

class MDialogBox:public MWindow
{
public:
    MDialogBox(){};
    ~MDialogBox(){};

    void show(){};
    //...
};

void f(MWindow& w)
{
    typedef MDialogBox& RDIALOG;

    if (typeid(w)==typeid(MWindow))
        w.show();
    else
    if (typeid(w)==typeid(MDialogBox))
        RDIALOG(w).show();
}

int main()
{
    MWindow* pw=new MWindow;
    MWindow* pd=new MDialogBox;

    f(*pw); //invokes MWindow::show()
    f(*pd); //invokes MDialogBox::show()

    delete pw;
    delete pd;

    return 0;
}