#include #include class Base { public: std::string public_member = "Base_Public"; void public_method() { std::cout << "Base::public_method()" << std::endl; } protected: std::string protected_member = "Base_Protected"; void protected_method() { std::cout << "Base::protected_method()" << std::endl; } private: std::string private_member = "Base_Private"; void private_method() { std::cout << "Base::private_method()" << std::endl; } }; // Public Inheritance class DerivedPublic : public Base { public: void access_base_members() { std::cout << "DerivedPublic accessing:" << std::endl; std::cout << " " << public_member << std::endl; // 正确 public_method(); // 正确 std::cout << " " << protected_member << std::endl; // 正确 protected_method(); // 正确 // std::cout << private_member << std::endl; // 错误：在 Base 中是 private 成员 // private_method(); // 错误：在 Base 中是 private 成员 } }; // Protected Inheritance class DerivedProtected : protected Base { public: void access_base_members() { std::cout << "DerivedProtected accessing:" << std::endl; std::cout << " " << public_member << std::endl; // 正确 (变为 protected) public_method(); // 正确 (变为 protected) std::cout << " " << protected_member << std::endl; // 正确 (保持 protected) protected_method(); // 正确 (保持 protected) } }; // Private Inheritance class DerivedPrivate : private Base { public: void access_base_members() { std::cout << "DerivedPrivate accessing:" << std::endl; std::cout << " " << public_member << std::endl; // 正确 (变为 private) public_method(); // 正确 (变为 private) std::cout << " " << protected_member << std::endl; // 正确 (变为 private) protected_method(); // 正确 (变为 private) } }; class GrandChildOfProtected : public DerivedProtected { public: void access_base_via_derived_protected() { std::cout << "GrandChildOfProtected accessing:" << std::endl; // public_member 在 Base 中是 public，在 DerivedProtected 中变为 protected std::cout << " " << public_member << std::endl; // 正确 public_method(); // 正确 // protected_member 在 Base 中是 protected，在 DerivedProtected 中保持 protected std::cout << " " << protected_member << std::endl; // 正确 protected_method(); // 正确 } }; int main() { std::cout << "--- DerivedPublic Demo ---" << std::endl; DerivedPublic d_pub; d_pub.access_base_members(); std::cout << "Accessing from main: " << d_pub.public_member << std::endl; // 正确 d_pub.public_method(); // 正确 // std::cout << d_pub.protected_member << std::endl; // 错误：protected 成员 // d_pub.protected_method(); // 错误：protected 成员 std::cout << "\\n--- DerivedProtected Demo ---" << std::endl; DerivedProtected d_prot; d_prot.access_base_members(); // std::cout << d_prot.public_member << std::endl; // 错误：public_member 在 DerivedProtected 中现在是 protected 的 // d_prot.public_method(); // 错误：public_method 在 DerivedProtected 中现在是 protected 的 GrandChildOfProtected gc_prot; gc_prot.access_base_via_derived_protected(); std::cout << "\\n--- DerivedPrivate Demo ---" << std::endl; DerivedPrivate d_priv; d_priv.access_base_members(); // std::cout << d_priv.public_member << std::endl; // 错误：public_member 在 DerivedPrivate 中现在是 private 的 // d_priv.public_method(); // 错误：public_method 在 DerivedPrivate 中现在是 private 的 return 0; }

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