急！虚函数的继承问题！

[xzyhero]

请教：在MFC中的类都是从CObject类中派生的，而CObject中的几个虚函数可以在所有派生类中的实例中通过调试工具的“Watch”可以看到vfptr.但是我们知道CCmdTarget类也是从CObject类中派生的，而CCmdTarget类中也有相应的Overridables函数，但是在CCmdTarget的派生类中确不能够看到CCmdTarget类的虚函数，请问是怎么一回事？

[xzyhero]

美人？

[phoenixli]

UP

[xzyhero]

http://expert.csdn.net/Expert/TopicView1.asp?id=2014140
尽管这个帖子中给出了所谓的答案，但是在实际的查看中还是不能够看到CCmdTarget的虚函数。

[glacierrr]

http://expert.csdn.net/Expert/TopicView1.asp?id=2014140

这个帖子里面的解法好像有问题，我加了class C : public B
还是达不到"这样你就能看到Func3了"!只能看到最基类的虚函数

[xzyhero]

是啊，郁闷！这样的话和虚函数的一般定义不是冲突了吗？

[xzyhero]

英雄所见略同，高手快进来！

[jruv]

这只能说明VC调试器也有其局限之处!

[xzyhero]

恩，jruv说得对，其实在虚函数表中的确有相应的内容。

[xzyhero]

#include <iostream>
using namespace std;

class Base1 {
public:
Base1() {
cout << "In Base1" << endl;
cout << "Virtual Pointer = " << (int*)this << endl;
cout << "Address of Vtable = " << (int*)*(int*)this << endl;
cout << "Value at Vtable 1st entry = " << (int*)*((int*)*(int*)this+0) << endl;
cout << "Value at Vtable 2nd entry = " << (int*)*((int*)*(int*)this+1) << endl;
cout << endl;
}
virtual void f() { cout << "Base1::f" << endl; }
virtual void g() { cout << "Base1::g" << endl; }
};

class Base2: public Base1{
public:
Base2() {
cout << "In Base2" << endl;
cout << "Virtual Pointer = " << (int*)this << endl;
cout << "Address of Vtable = " << (int*)*(int*)this << endl;
cout << "Value at Vtable 1st entry = " << (int*)*((int*)*(int*)this+0) << endl;
cout << "Value at Vtable 2nd entry = " << (int*)*((int*)*(int*)this+1) << endl;
cout << "Value at Vtable 3nd entry = " << (int*)*((int*)*(int*)this+2) << endl;
cout << "Value at Vtable 4nd entry = " << (int*)*((int*)*(int*)this+3) << endl;
cout << endl;
}

virtual void h() { cout << "Base2::h" << endl; }
virtual void j() { cout << "Base2::j" << endl; }
};

class Drive : public Base2 {
public:
Drive() {
cout << "In Drive" << endl;
cout << "Virtual Pointer = " << (int*)this << endl;
cout << "Address of Vtable = " << (int*)*(int*)this << endl;
cout << "Value at Vtable 1st entry = " << (int*)*((int*)*(int*)this+0) << endl;
cout << "Value at Vtable 2nd entry = " << (int*)*((int*)*(int*)this+1) << endl;
cout << "Value at Vtable 3nd entry = " << (int*)*((int*)*(int*)this+2) << endl;
cout << "Value at Vtable 4nd entry = " << (int*)*((int*)*(int*)this+3) << endl;
cout << endl;
}
virtual void f() { cout << "Drive::f" << endl; }
// virtual void g() { cout << "Drive::g" << endl; }
virtual void h() { cout << "Drive::h"<<endl;}
};

int main() {

int temp;

Drive objDrive;
objDrive.h ();
}