c – 派生类私有方法被调用
作者：互联网
我有一个指向派生类对象的Base类指针.方法foo()在基类中是公共的,但在派生类中是私有的.基类foo()是虚拟的.因此,当我从Base类指针调用foo()时,Vptr Table具有派生类foo()的地址,但它在Derived类中是私有的……所以如何调用它.
我理解运行时多态性,我也理解Access说明符适用于编译时,虚拟概念在运行时工作.所以应该没有编译器错误.
我的问题是：这是一个循环漏洞,通过它我们可以调用派生类的私有方法吗？或者它的预期表现如此.
对此行为有任何好的解释.
非常感谢提前.
代码：
class A
{
public:
virtual void foo()
{
std::cout << "In A";
}
};
class B:public A
{
private:
void foo()
{
std::cout << "In B ??? Its Private Method :-( ";
}
};
int main()
{
A* ptr = new B();
ptr->foo();
return 0;
}
解决方法:
它是私有方法,但由于它是虚拟的 – 它可以被调用.
n3690 11.5 / 1
The access rules (Clause 11) for a virtual function are determined by its declaration and are not affected by
the rules for a function that later overrides it.
为什么这个？以来
n3690 11.5 / 2
Access is checked at the call point using the type of the expression used to denote the object for which the
member function is called (B* in the example above). The access of the member function in the class in
which it was defined (D in the example above) is in general not known.