在国外一个网站中，其中一道题目自己理解不太明白，所以，在此，自己用程序实现一下，以便更好的理解。参考部分代码如下：

.......
.......
class A {
private:
	int i;
public:
	virtual void vfoo(){
		cout<<"Base"<<endl;
	}
	A():i(0){
		cout<<"i:"<<i<<endl;
		cout<<"initial A()"<<endl;
	}
	~A(){
		cout<<"Delete A()"<<endl;
	}
};

class B:public A{
private:
	int j;
public:
	void vfoo(){
		j++;
		cout<<"j:"<<j<<endl;
		cout<<"Derived"<<endl;
	}
	B():j(0){
		cout<<"j:"<<j<<endl;
		cout<<"Initial B()"<<endl;
	}
	~B(){
		cout<<"Delete B()"<<endl;
	}
};

class C:public B{
private:
	int k;
public:
	C():k(0){
		cout<<"k:"<<k<<endl;
		cout<<"Initial C()"<<endl;
	}
	~C(){
		cout<<"Delete C()"<<endl;
	}
};
.......
.......
class AA{
 ........
};
.......

测试主程序：

int main(){
	A *p, oa;
	C oc;

	p = &oa;
	p->vfoo();

	p =&oc;
	p->vfoo();
	return 0;
}

i:0
initial A()
i:0
initial A()
j:0
Initial B()
k:0
Initial C()
Base
j:1
Derived 
Delete C()
Delete B()
Delete A()
Delete A()

C++ --virtual funcation and overload