Virtual Function in C++

 

#include<bits/stdc++.h>

using namespace std;

class Aakash{

    protected:

    string Name;

    int roll;

    public:

    Aakash(string s, int r){

        Name = s;

        roll = r;

    }

  virtual void display()=0;      // abstract base class mean pure virtual class and pure virtual class means

                                    //   minimum one funtion of base class should be virtual

};

class AK1: public Aakash{

    int plan;

    public:

    AK1(string s, int r , int p): Aakash(s,r){

        plan=p;

    }

    void display(){

        cout<<"The Name is: "<<Name<<endl;

        cout<<"The Roll No is: "<<roll<<endl;

        cout<<"The No's of Plan is: "<<plan<<endl<<endl;

    }

};

class AK2: public Aakash{

    int plan2;

    public:

    AK2(string s, int r , int p2): Aakash(s,r){

        plan2=p2;

    }

    void display(){

        cout<<"The Name is: "<<Name<<endl;

        cout<<"The Roll No is: "<<roll<<endl;

        cout<<"The No's of Plan is: "<<plan2<<endl;

    }

};

int main()

{   string Name;

    int roll;

    int plan,plan2;

    Name = "Aakash";

    roll = 4025;

    plan = 24;

    plan = 24;

    AK1 vk(Name,roll,plan);

   // vk.display();

     Name = "Karan";

    roll = 4042;

    plan = 25;

    plan = 24;

    AK2 kv(Name,roll,plan);

   // kv.display();

    Aakash * ok[2];

    ok[0] = &vk;

    ok[1] = &kv;

     ok[0]->display();

     ok[1]->display();

   

    return 0;

}