为什么我不能从派生类的实例访问受保护的成员?
我有一段时间没有使用 C++，无法弄清楚为什么以下不起作用:
I haven't done C++ in a while and can't figure out why following doesn't work:
class A {
protected:
int num;
};
class B : public A {
};
main () {
B * bclass = new B ();
bclass->num = 1;
}
编译产生:
错误 C2248:A::num":无法访问类A"中声明的受保护成员
error C2248: 'A::num' : cannot access protected member declared in class 'A'
派生类不应该访问受保护的成员吗?
Shouldn't protected members be accessible by derived classes?
我错过了什么?
推荐答案
是的，派生类可以访问受保护的成员，但是您正在 main() 函数中访问它，该函数在层次结构之外.如果你在 B 类中声明一个方法并访问 num 就可以了.
yes protected members are accessible by derived classes but you are accessing it in the main() function, which is outside the hierarchy. If you declare a method in the class B and access num it will be fine.
相关文章