Hi ,
I encountered an issue like , I have a base class with one virtual
function and one derived class for it. I have overridden the virtual method. I
have a function which will accept an array of base class objects. and I am
printing the virtual method in this function. I have passed address of derived
class array objects. I could access non - virtual functions of base class but
couldn't access the virtual methods. I thought like there could be an issue
with size like derived could be larger than base and while incrementing the
base pointer , I am getting issue like. But after some r&d I figured out that
is not the issue. I am copy pasting the sample code snippet . Could any one of
you please assist.
#include "stdafx.h"
typedef void (*myfun)();
class polybase
{
public:
void disp()
{
cout<<"I am in disp of base"<<endl;
}
virtual void show()
{
cout<<"I $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$sam in base"<<endl;
}
};
class polyder:public polybase
{
public:
void show()
{
cout<<"=======================================I am in der"<<endl;
}
};
void disp(polybase **x)
{
myfun objfun;
objfun = (myfun )*(int *)*(int *)(&x[0]); //(Just to check whether I could
access the
//(virtual methods and I
am done.)
objfun();
x[0]->disp();
x[1]->disp(); // I could access disp of second object in array ..
x[0]->show(); // I am getting access violation error here.
x[1]->show();
cout<<endl;
cout<<&x[0]<<endl;
cout<<"size is"<<sizeof(x[0])<<endl;
}
void func(polybase *x)
{
x->show();
x->disp();
}
int main(int argc, char* argv[])
{
polyder obj[2];
// polybase obj[2];
cout<<"The size is "<<sizeof(obj[0])<<endl;
obj[0].show();
myfun objfun;
objfun = (myfun )*(int *)*(int *)(&obj[0]);
objfun();
disp((polybase **)&obj);
func((polybase *)&obj1); // If I pass a single object instead of array , I
could
//access virtual functions properly. )
polybase *x = &obj1;
x->show();
return 0;
}
Thanks & Regards,
Gopi.k
Software Engg.
PAY PAL,
Chennai.
9884609596
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