在Bjarne第三版的书中，1.3节中说明了：A C++ nested class does not have access to an object of the enclosing class.

然而在16.2.13中又写到：
A member class (often called a nested class) can refer to types and static members of its enclosing class. It can only refer to non-static members when it is given an object of the enclosing class to refer to. To avoid getting into the intricacies of binary trees, I use purely technical ‘‘f() and g()’’-style examples.
A nested class has access to members of its enclosing class, even to private members (just as a member function has), but has no notion of a current object of the enclosing class.

今天早上我先是被AI给绕晕了，接着我又把AI给绕晕了
```cpp
class Encloser {
private:
  struct PrivateType {/* many code here */};
  class Nester {
   public:
    inline const PrivateType& Show() { return member_; }
   private:
    PrivateType member_;
};
};
```
这段代码请各位评析一下是否可以？
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FROM 36.163.208.*

结论：
1. 嵌套类可以使用外部类中定义的私有类型，无须加命名域符；
2. 嵌套类中无法直接访问外部类的成员变量和成员函数，无论公有私有都不行。

用下面的代码测试过了，嵌套类（成员类）可以使用外部类的私有类型(type)但是不能访问外部类中的私有成员变量，也不能调用外部类中的成员函数。
/*!
* This test code shows nested class can use the private type of enclosing
* class, but cannot access the members and functions of enclosing class, no
* matter private and public
*/
#include <iostream>
class Encloser {
public:
  Encloser(double x, double y, double k1 = 1.0, double k2 = 1.0)
      : member_(Nester(x, y)), k1_(k1), k2_(k2) {}
  double Calculate() { return (member_.Show().x_ + member_.Show().y_) * k1_ * k2_; }
  double Add(double a, double b) { return a + b; }
  double k2_ = 1.0;

private:
  class PrivateClass {
   public:
    double x_;
    double y_;
  };
  class Nester {
   public:
    Nester(double x, double y) : member_({x, y}) {}
    inline const PrivateClass& Show() { return member_; }
    // inline double ShowK1() { return k1_; }
    // inline double showK2() { return k2_; }
    double InnerCalculate() {
      double result = 0.0;
      // result = Add(member_.x_, member_.y_);
      // result = Product(result, k1_);
      //   result = Product(result, k2_);
      return result;
    }

   private:
    PrivateClass member_;
  };
  double k1_ = 1.0;
  Nester member_;
  double Product(double a, double b) { return a * b; }
};

int main() {
  Encloser enclose_object(2.0, 3.0, 4.0);
  std::cout << "The result is: " << enclose_object.Calculate() << std::endl;
  return 0;
}


【 在 foliver 的大作中提到: 】
: 嵌套类没有父类都this指针，所有需要用到父类的都不可以。你这代码显然不行。
: 嵌套类是父类都一个成员，所以父类的变量访问权限通通对嵌套类开放。
:
--
修改:wanllow FROM 36.163.208.*
FROM 36.163.208.*

按你的方法轻松搞定了，
我也不想用太花骚的招式，只要能解决问题就好，
然而新手经常会被AI误导，它们说这种情况必须用嵌套才够安全，不会泄漏。
我后来想了想，谁会没事来动我的代码呀，先搞定再说，泄漏了也不怪我
【 在 z16166 的大作中提到: 】
: 感觉嵌套类很少用，我一般都是在class内部定义一些struct而不是定义class
: 需要定义嵌套class的地方，我都是拆出来单独定义，放到同一个namespace里
: 感觉花精力在这上面不太值
: ...................
--
FROM 36.163.208.*