/*
 * Simple structure.
 */
package main

import "fmt"
import "math"

/*
 * The Point again.
 */
type Point struct {
	x, y float64
}

/*
 * Go allows methods to declare a "receiver," which allows them to be
 * called as methods of the recevier's type.
 */
func (p *Point) to_s() string {
	return fmt.Sprintf("(%g,%g)", p.x, p.y)
}

func (from *Point) distance(to *Point) float64 {
	dx := from.x - to.x
	dy := from.y - to.y
	return math.Sqrt(dx*dx + dy*dy)
}

func main() {
	// Create a point by declaration.
	var origin Point
	fmt.Println(origin.to_s())
		
	var p1 Point = Point{4.8,-3.11}
	p2 := Point{y: -3.0, x: 4.1}
	fmt.Println(p1.to_s(), "to", p2.to_s(), "is", p1.distance(&p2))

	var p3 *Point = new(Point)
	*p3 = Point{y: 3.2}
	var p4 *Point = new(Point)
	*p4 = Point{5.1,2.2}
	fmt.Println(p3.to_s(), "to", p4.to_s(), "is", p3.distance(p4))
}