#include <iostream>
#include <string>

using namespace std;

class Person
{
public:
  Person(int s, const string & n = "")
    : ssn(s), name(n)
  { }

  virtual ~Person()
  {}
  
  const string & getName() const
  { return name; }

  int getSsn() const
  { return ssn; }

  virtual void print(ostream & out = cout) const
  { out << ssn << ", " << name; }

private:
  int ssn;
  string name;
};

ostream & operator<<(ostream & out, const Person &p)
{
  p.print(out);
  return out;
}



class Student : public Person
{
public:
  Student(int s, const string &n="", double g=0.0)
    : Person(s, n), gpa(g)
  {}

  double getGpa() const
  { return gpa; }

  void print(ostream &out=cout) const
  { Person::print(out); out << ", " << gpa; }

private:
  double gpa;
};



class Teacher : public Person 
{
public:
  Teacher(int s, const string &n="", const string &d="")
    : Person(s, n), department(d)
  {}

  string getDepartment() const
  { return department; }

  void print(ostream &out=cout) const
  { Person::print(out); out << ", " << department; }

private:
  string department;
};

int main()
{
  Person p(987654321, "Bob");
  Student s(123456789, "Jane", 4.0);
  Teacher t(326382700, "Richard", "CSE");

  cout << "--- Print using operatop<< ---" << endl;
  cout << p << endl << s << endl << t << endl;

  cout << "--- Print using print methods ---" << endl;
  // If Person::print was declared to be "virtual", then
  // The following lines will give the same output as above.
  // Otherwise, they will be different.
  
  p.print(cout);
  cout << endl;
  s.print(cout);
  cout << endl;
  t.print(cout);
  cout << endl;

  cout << "--- Dynamic Cast Demo ---" << endl;

  Person *pp1 = &s;
  Person *pp2 = &t;

  Student *ps1 = dynamic_cast<Student*>(pp1);
  Student *ps2 = dynamic_cast<Student*>(pp2);

  cout << "ps1 = " << ps1 << endl << "ps2 = " << ps2 << endl;

  return 0;
}