#include <cstdlib>   //for exit, EXIT_FAILURE
#include <cmath>     //for sqrt and atan2
#include "point.h"
using namespace std;

const int point::subscript = ostream::xalloc();

ostream& operator<<(ostream& ost, const point& p)
{
	switch (ost.iword(point::subscript)) {

	case 0:
		//Cartesian coordinates.
		return ost << "(" << p.x << ", " << p.y << ")";

	case 1:
		//Polar coordinates.
		if (p.x == 0.0 && p.y == 0.0) {
			return ost << "(" << 0.0 << ", " << 0.0 << ")";
		} else {
			return ost << "(" << sqrt(p.x * p.x + p.y * p.y) << ", "
				<< atan2(p.y, p.x) << ")";
		}

	default:
		cerr << "iword(" << point::subscript << ") == "
			<< ost.iword(point::subscript)
			<< " is neither 0 (Cartesian) nor 1 (polar).\n";
		exit(EXIT_FAILURE);
	}
}