Pointer Receivers

pointer_receivers.go

package main

import (
	"fmt"
	"math"
)

type Point struct {
	X, Y float64
}

func (p Point) Distance(q Point) float64 {
	return math.Hypot(q.X-p.X, q.Y-p.Y)
}

func (p *Point) ScaleBy(factor float64) {
	p.X *= factor
	p.Y *= factor
}

func main() {
	r := &Point{1, 2}
	r.ScaleBy(2)
	fmt.Println(*r)

	p := Point{1, 2}
	pptr := &p
	pptr.ScaleBy(2) // is implicitly:
	(*pptr).ScaleBy(2)
	fmt.Println(p)

	q := Point{1, 2}
	q.ScaleBy(2) // is implicitly:
	(&q).ScaleBy(2)
	fmt.Println(q)

	s := Point{1, 2}.Distance(q)
	fmt.Println(s)

}