begin
comment distance between two points;
	real dist;
	record RPoint (real x, y);
	reference(RPoint) pt1;
	reference(RPoint) pt2;
	
	pt1 := RPoint(1.0, 2.0);
	pt2 := RPoint(2.0, -2.0);
	
	dist := (x(pt2)-x(pt1))**2 + (y(pt2)-y(pt1))**2;
	dist := sqrt(dist);
	write(dist);
end.