限制继承

Question

class BaseA {}; ,类DerivedB {}; class DerivedC {};

DerivedB可以从BaseA派生:想要允许:class DerivedB:public BaseA

但是,如果有人试图做DerivedC:public BaseA ==>想要限制它.

可能吗？

Answer 1

你可以让所有BaseA的构造私人和添加DerivedB作为一个friend的BaseA的.

class BaseA
{
    friend class DerivedB;
private:
    BaseA();
};
class DerivedB : BaseA
{
};
class DerivedC : BaseA  //error - I get it when I try to create an object in MSVS
                        //but in principle it works
{
};