#include <iostream>

using namespace std;


struct User {
	void show_base () {
        cout << "[User]" << endl;
		cout << "private:   " << this->_private   << endl; // Работает => private
		cout << "protected: " << this->_protected << endl; // Работает => protected
		cout << "public:    " << this->_public    << endl; // Работает => public
        cout << endl;
	}

private:
	string _private = "access";

protected:
	string _protected = "access";

public:
	string _public = "access";
};

struct UserTools : public User {
	void show_tools () {
        cout << "[UserTools]" << endl;
		cout << "private:   " << "ERROR"          << endl; // ERROR    => private
		cout << "protected: " << this->_protected << endl; // Работает => protected
		cout << "public:    " << this->_public    << endl; // Работает => public
        cout << endl;
	}
};

int main () {
	UserTools user;

    user.show_base();
    user.show_tools();

    cout << "[main]" << endl;
	cout << "private:   " << "ERROR"      << endl; // ERROR    => private
	cout << "protected: " << "ERROR"      << endl; // ERROR    => protected
	cout << "public:    " << user._public << endl; // Работает => public
}