package main

// Go supports methods defined on struct types

import "fmt"

type rect struct {
	width, height int
}

// This area method has a receiver type of *rect
func (r *rect) area() int {
	return r.width * r.height
}

// value receiver
func (r rect) perim() int {
	return 2*r.width + 2*r.height
}

func main() {
	r := rect{width: 10, height: 5}

	fmt.Println("area: ", r.area())
	fmt.Println("perim: ", r.perim())

	// Go automatically handles conversion between values
	// and pointers for method calls. You may want to use a
	// pointer receiver type to avoid copying on method calls
	// or to allow the method to mutate the receiving struct.
	rp := &r
	fmt.Println("area: ", rp.area())
	fmt.Println("perim: ", rp.perim())
}