Thread: Why Virtual base class increase the size of class by 4 bytes?

Hi all,

Well I have a quick doubt on virtual base class:
can sombody explain?
I am going to write 2 c++ program please check output.

Code:

#include<iostream>
using namespace std;

class base
{
	int i;
};

class derived: public base
{
};


void main()
{
	cout<<"size of class derived is "<<sizeof(derived)<<endl;
}


OUTPUT:
size of class derived is 4
Press any key to continue


With virtual:

#include<iostream>
using namespace std;

class base
{
	int i;
};

class derived:virtual public base
{
};


void main()
{
	cout<<"size of class derived is "<<sizeof(derived)<<endl;
}

OUTPUT:
size of class derived is 8
Press any key to continue