Defining methods on values or pointers

method_value_or_pointer.go

package main

import (
	"fmt"
)

type rectPointer struct {
	width  int
	height int
}

func (r *rectPointer) Print() {
	fmt.Printf("width: %v, height: %v\n", r.width, r.height)
}

func (r *rectPointer) set(w, h int) {
	r.width = w
	r.height = h
}

type rectValue struct {
	width  int
	height int
}

func (r rectValue) Print() {
	fmt.Printf("width: %v, height: %v\n", r.width, r.height)
}

func (r rectValue) set(w, h int) {
	r.width = w
	r.height = h
}

func main() {
	fmt.Println("Pointer")
	rp := rectPointer{width: 10, height: 5}
	rp.Print()

	rp.set(100, 100)
	rp.Print()
	// Pointer
	//width: 10, height: 5
	//width: 100, height: 100

	fmt.Println()

	fmt.Println("Value")
	rv := rectValue{width: 10, height: 5}
	rv.Print()

	rv.set(100, 100)
	rv.Print()
	// Value
	//width: 10, height: 5
	//width: 10, height: 5
}