how to determine the size of virtual base class and derived classes from it?

Question

#include 
using namespace std;

class base1{};
class base2{virtual void show(){}};

class test1{    };
class test2{virtual void show(){}};

class der         


        

Answer 1

An Empty class inheriting a base class in virtual (access specifier ) mode (ex.virtual public) has size of 8 while if is non-empty it would have a size of 16.