#include <iostream>
using namespace std;
class A
{
public:
virtual void Func1()
{
cout << "class A Func1" << endl;
}
virtual void Func2()
{
cout << "class A Func2" << endl;
}
};
class B
{
public:
virtual void Func1()
{
cout << "class B Func1" << endl;
}
void Func2()
{
cout << "class B Func2" << endl;
}
virtual void Func3()
{
cout << "class B Func3" << endl;
}
};
int* GetFuncAddr(void* p, int offer)
{
//p相當於this指針,off表示虛函數表索引項
int* v_ptrAdrs = *((int**)p);
return *((int**)v_ptrAdrs + offer);
}
typedef void (*gFUNC)();
void AFunc1Helper(A *p)
{
//直接調用虛函數
(*(gFUNC)GetFuncAddr(p, 0))();
}
//爲每一個虛函數,實現一個輔助函數,用於指定虛函數表中的索引項
void AFunc2Helper(A *p)
{
(*(gFUNC)GetFuncAddr(p, 1))();
}
void BFunc1Helper(B *p)
{
(*(gFUNC)GetFuncAddr(p, 0))();
}
void BFunc3Helper(B *p)
{
(*(gFUNC)GetFuncAddr(p, 1))();
}
int _tmain(int argc, _TCHAR* argv[])
{
A *pa = new A;
B *pb = new B;
//交換AB虛表指針
int v_ptr = *((int*)pa);
*((int*)pa) = *((int*)pb);
*((int*)pb) = v_ptr;
//pa->Func1();
AFunc1Helper(pa);
//pa->Func2();
AFunc2Helper(pa);
//pb->Func1();
BFunc1Helper(pb);
pb->Func2();
//pb->Func3();
BFunc3Helper(pb);
return 0;
}