Pointer_026_pure_virtual.cpp

// pure virtual function
#include <iostream>
using namespace std;
////////////////////////////////////////////////////////////////
class Base //base class
{
public:
    virtual void show() = 0; //pure virtual function
};
////////////////////////////////////////////////////////////////
class Derv1 : public Base //derived class 1
{
public:
    void show()
    {
        cout << "Derv1\n";
    }
};
////////////////////////////////////////////////////////////////
class Derv2 : public Base //derived class 2
{
public:
    void show()
    {
        cout << "Derv2\n";
    }
};
////////////////////////////////////////////////////////////////
int main()
{
// Base bad; //can’t make object from abstract class
    Base* arr[2]; //array of pointers to base class
    Derv1 dv1; //object of derived class 1
    Derv2 dv2; //object of derived class 2
    arr[0] = &dv1; //put address of dv1 in array
    arr[1] = &dv2; //put address of dv2 in array
    arr[0]->show(); //execute show() in both objects
    arr[1]->show();
    return 0;
}

//Derv1
//Derv2