Inheritance and Mode of Inheritance in C++

Program 1

// Inheritance in CPP
#include<iostream>
using namespace std;
class Base
{
    private:
     void a_private()
     {
        cout<<"Private method";
     }
    protected:
      void a_protected()
     {
        cout<<"Protected method";
     }
     public:
      void a_public()
     {
        cout<<"Public method";
     }
};
class Derived: public Base   // is A Relation
{
     private:
     
     protected:
      
     public:
     void abc()
     {
         a_protected();
     }
};

int main()
{
    system("cls");
   Derived D;
   D.a_public();
   D.abc();
    return 0;
}

Program 2

// Inheritance in CPP
#include<iostream>
using namespace std;
class Base
{
     public:
       int a_pub=100;
     private:
     int a_pri=300;
     protected:
     int a_pro=500;

};
class Derived:protected Base
{
   
};
int main()
{
    system("cls");
     Derived D;
     

     return 0;
}