// CS1621
// Demo of simple polymorphism in C++.  Compare to poly.java and the related
// class files

// Note: After class on Monday, November 28, I added destructors to this
// program, so you could see the sequence of calls.  I recommend running
// this yourselves to see what happens.

#include <iostream>
#include <string>
using namespace std;

class People
{
      private:
          string name;
          int age;
      public:
          People()
		  { cout << "People default constructor: " << this << endl;}
          
          People(string s, int i)
          {
              name = s;
              age = i;
			  cout << "People constructor: " << this << endl;
          }

          virtual void Insert(ostream& ostr)
          {
              ostr << "Name: " << name << " Age: " << age;
          }

		  virtual ~People()
		  { cout << "People destructor: " << this << endl; }
};

class Student: public People
{
      private:
          string major;
          double gpa;
      public:
          Student(string s, int i, string mymajor, double mygpa):
                     People(s, i)
          {
              major = mymajor;
              gpa = mygpa;
			  cout << "Student constructor: " << this << endl;
          }

          virtual void Insert(ostream& ostr)
          {
              People::Insert(ostr);
              ostr << " Major: " << major << " GPA: " << gpa;
          }

		  ~Student()
		  { cout << "Student destructor: " << this << endl; }
};

class Worker: public People
{
      private:
          double salary;
      public:
          Worker(string s, int i, double mysalary): People(s, i)
          {
              salary = mysalary;
			  cout << "Worker constructor: " << this << endl;
          }

          virtual void Insert(ostream& ostr)
          {
              People::Insert(ostr);
              ostr << " Salary: " << salary;
          }

		  ~Worker()
		  { cout << "Worker destructor: " << this << endl; }

};

int main()
{
     // To utilize polymorphism in C++, pointers (or references) must be used
     People ** P = new People * [6];

     P[0] = new People("Herb", 25);
     P[1] = new Worker("Bart", 60, 85000);
     P[2] = new Worker("Zeke", 32, 45000);
     P[3] = new Student("Bill", 20, "CS", 3.5);
     P[4] = new Student("Mary", 18, "English", 3.8);
     P[5] = new People("Alice", 40);

     for (int i = 0; i < 6; i++)
     {
          P[i] -> Insert(cout);
          cout << endl;
     }
     cout << endl;

	 for (int i = 0; i < 6; i++)
		 delete P[i];

     // Now lets do the same thing with static objects and no pointers.  The
     // syntax is still legal, but note that the function called is now always
     // the one from the People class, since the array is an array of People
     People P2[6];
     P2[0] = People("Herb", 25);
     P2[1] = Worker("Bart", 60, 85000);
     P2[2] = Worker("Zeke", 32, 45000);
     P2[3] = Student("Bill", 20, "CS", 3.5);
     P2[4] = Student("Mary", 18, "English", 3.8);
     P2[5] = People("Alice", 40);

     for (int i = 0; i < 6; i++)
     {
          P2[i].Insert(cout);
          cout << endl;
     }

}