c++ - 内部/嵌套类-私有(private)和公共(public)之间的区别

Question

我有内部嵌套类，它是私有(private)的:

   class Client{
   private:
      class Inner;
      Inner *i;

如果我将 Inner 类公开而 Inner *i 保持私有(private)，究竟会发生什么？会发生什么，对程序执行有什么影响？

Answer 1

考虑以下案例用法:

class Client
{
private:
    class Inner {};
    Inner *i;

    class Inner2 {};
public:
    class Inner3 {};
    Inner3 *j;

public:
    Inner2 *k;
};

void main()
{
    Client c;

    c.i = nullptr; //error: you cant access the private members

    c.j = nullptr; //ok: member is public
    c.k = nullptr; //ok: same here, member is public, even if it's type is private

    Client::Inner3 i3;//ok: to declare since Inner3 is declared public

    Client::Inner2 i3;//error: can't access private members of type declarations

}

除此之外，程序的执行在任何情况下都不受私有(private)/公共(public)或 protected 影响。