What are the differences between protected and private inheritance?

概念

the differences between protected and private inheritance primarily relate to the accessibility of base class members in derived classes and outside the class hierarchy:

例子

#include <iostream>
using namespace std;

class Base
{
private:
    int pvt = 1;

protected:
    int prot = 2;

public:
    int pub = 3;

    // function to access private member
    int getPVT() { return pvt; }
};

class ProtectedDerived : protected Base
{
public:
    // function to access protected member from Base
    int getProt() { return prot; }

    // function to access public member from Base
    int getPub() { return pub; }

    // function to get access to private members from Base
    int try_getPVT() { Base::getPVT(); }
};

int main()
{
    ProtectedDerived object1;
    cout << "Private = " << object1.try_getPVT() << endl;
    cout << "Protected = " << object1.getProt() << endl;
    cout << "Public = " << object1.getPub() << endl;
    return 0;
}