#include <iostream>
using namespace std;class Base1
{
public:int m_base1;inline virtual void vfBase1_1(){cout << "This is in Base1::vfBase1_1()" << endl;}inline virtual void vfBase1_2(){cout << "This is in Base1::vfBase1_2()" << endl;}
};
class Base2
{
public:int m_base2;inline virtual void vfBase2_1(){cout << "This is in Base2::vfBase2_1()" << endl;}inline virtual void vfBase2_2(){cout << "This is in Base2::vfBase2_2()" << endl;}
};
class Base3
{
public:int m_Base3;inline virtual void vfBase3_1(){cout << "This is in Base3::vfBase3_1()" << endl;}inline virtual void vfBase3_2(){cout << "This is in Base3::vfBase3_2()" << endl;}
};
class Derived : public Base1, public Base2, public Base3
{
public:int m_derived;inline virtual void fd(){cout << "This is in Derived::fd()" << endl;}
};
typedef void (*VFun)(void);
template<typename T>
VFun virtualFunctionPointer(T* b, int i)
{return (VFun)(*((int*)(*(int*)b) + i));
}
int main(void)
{Derived d;cout << "The size of Derived object = \t" << sizeof(Derived) << endl;cout << endl;cout << "1st virtual function table: " << endl;int i = 0;while(virtualFunctionPointer(&d, i)&&i<3){VFun pVF = virtualFunctionPointer(&d, i++);pVF();}cout << endl;cout << "2nd virtual function table: " << endl;i = 0;//以32字长的机器，找到下一个继承base class的vptrint* tmp = ((int*)&d)+ sizeof(Base1)/4;//虚函数表中的虚函数后面不为NULL？如果不加i的限制会出现段错误，不能结束循环while(virtualFunctionPointer(tmp, i)&&i<2){VFun pVF = virtualFunctionPointer(tmp, i++);pVF();}cout << endl;cout << "3rd virtual function table: " << endl;i = 0;tmp = ((int*)&d) +(sizeof(Base1)+sizeof(Base2))/4;while(virtualFunctionPointer(tmp, i)&&i<2){VFun pVF = virtualFunctionPointer(tmp, i++);pVF();}return 0;
}