无继承的公共成员
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我有一个基类，看起来像这样：
class Base
{
public:
typedef std::shared_ptr<Base> ptr_t;
typedef std::weak_ptr<Base> wptr_t;
enum class Type { foo, bar, baz };
Type x;
// ...
};
Base::ptr_t my_ptr(new Base);
class Derived : public Base
{
// ...
};
x
ptr_t
wptr_t
Type
Derived a;
a.x = Base::Type::foo; // this should work
a.x = Derived::Type::foo; // but I want this to fail
friend
virtual
没有找到相关结果
已邀请:
3 个回复
犀寺扦
class Derived { typedef int Type; };（因为它既是私有的又是）勺的驴吓识
class Derived : public Base { // This is now private using Base::ptr_t; using Base::wptr_t; // ... };迪擅哨乘傅
class Base { private: // only \'BaseClass\' is allowed to derive from Base Base() { } friend class BaseClass; public: typedef std::shared_ptr<Base> ptr_t; typedef std::weak_ptr<Base> wptr_t; enum class Type { foo, bar, baz }; Type x; // ... }; class BaseClass : public Base { private: // make all the raw_Base types private using Base::ptr_t; using Base::wptr_t; using Base::Type; }; class Derived : public BaseClass { // define as usual, and now all is well in the world. }; // now, to test it class Derived2 : public Base { }; // fails Derived d; d.x = Derived::Type::foo; // fails d.x = Base::Type::foo; // works // Which is exactly what I wanted.本身不能由派生而来，但是却是一个没有吸引力的命名空间杂物。 但是，对于我打算在其中使用的特定代码段，我碰巧已经在使用等价的ѭ17来解决一个不相关的问题。因此，这种技术非常适合我的目的。