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

class shape{
protected:
	double area;
public:
	shape():area(-1.0){}
	shape(double a):area(a){}
	// pure virtual - makes abstract class
	//virtual void print()=0;
	virtual void print(){cout << "SHAPE, area = " << area << endl;}
};

class wire: public shape{
public:
	int x1, y1, x2, y2;
	wire():shape(-3){}
	wire(double ar, int a, int b, int c, int d): shape(ar), x1(a), y1(b), x2(c), y2(d){}
	void print(){
		cout << "WIRE area " << area << endl;
		cout << " x1 " << x1 << " y1 " << y1 << endl;
		cout << " x2 " << x2 << " y2 " << y2 << endl;
	}
};

class transistor: public shape{
public:
	int x1, y1, x2, y2;
	string type;
	transistor():shape(-2),x1(0),y1(0),x2(0),y2(0){}
	transistor(double r, int a, int b, int c, int d):shape(r),x1(a),y1(b),x2(c),y2(d){}

	// redefined print
	void print(){
		cout << "TRANSISTOR, area = " << area << endl;
		cout << " x1 " << x1 << " y1 " << y1 << endl;
		cout << " x2 " << x2 << " y2 " << y2 << endl;
	}
	

};

void main(){
   // makes some shapes, wire and transistors and print
   shape s(3);
   transistor t1, t2(8.0, 0, 0, 2, 4);
   s.print();
   t1.print();
   t2.print();
   wire w(16,0,0,2,8);
   w.print();

   // do an array of objects
   shape sa[4];
   sa[0] = s;
   sa[1] = t1;
   sa[2] = t2;
   sa[3] = w;

   // see slicing in action!
   cout << endl << "sliced array " << endl;
   for(int i = 0; i < 4; i++)
	   sa[i].print();

   // polymorphism
   shape *sp[4];// array of pointers
   sp[0] = &s;
   sp[1] = &t1;
   sp[2] = &t2;
   sp[3] = &w;

   cout << endl << "polymorphic print " << endl;
   for(int i = 0; i < 4; i++)
	   sp[i]->print();

}