#include "point.h"
#include "line.h"

//Construct the point where the two lines intersect.
//Throw an exception if the two lines are parallel.

point::point(const line& l1, const line& l2) throw (int)
{
	const double a1 = l1.B.y - l1.A.y;
	const double b1 = l1.A.x - l1.B.x;
	const double c1 = b1 * l1.A.y + a1 * l1.A.x;

	const double a2 = l2.B.y - l2.A.y;
	const double b2 = l2.A.x - l2.B.x;
	const double c2 = b2 * l2.A.y + a2 * l2.A.x;

	const double determinant = a1 * b2 - a2 * b1;

	if (determinant == 0) {
		//lines are parallel
		throw 0;
	}

	x = (b2 * c1 - b1 * c2) / determinant;
	y = (a1 * c2 - a2 * c1) / determinant;
}