simple base and derived class example [override pure virtual function]

Bjarne Stroustrup “Programming Principles and Practice Using C++”
Chapter 14 Drill 6
Using std_lib_facilities.h by Bjarne Stroustrup.

[code language=”cpp”]
// Philipp Siedler
// Bjarne Stroustrup’s PP
// Chapter 14 Drill 6

#include "std_lib_facilities.h"
using namespace std;

class B1
{
public:
virtual void vf() { cout << "B1::vf" << endl; }
void f() { cout << "B1::f" << endl; }
virtual void pvf() = 0;
};

class D1 : public B1
{
public:
void vf() { cout << "D1::vf" << endl; }
void f() { cout << "D1::f" << endl; }
void pvf() { cout << "D1::pvf" << endl; }
};

class D2 : public D1
{
public:
void pvf() { cout << "D2::pvf" << endl; }
};

int main()
try
{
D2 d2_0;
d2_0.f();
d2_0.vf();
d2_0.pvf();

keep_window_open();
}
catch (exception& e) {
cout << e.what() << endl;
return 1;
}
catch (…) {
cout << "Exiting" << endl;
return 2;
}
[/code]

Output:
D1::f
D1::vf
D2::pvf
Please enter a character to exit