(Go Lang) Methods (GBEN)

package main
import "fmt"
// Go supports methods defined on struct types.
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
}
// Methods can be defined for either pointer or value receiver types. Here’s
// an example of a value receiver.
func (r rect) perim() int {
  return 2*r.width + 2*r.height
}
func main() {
  r := rect{width: 10, height: 5}
  // Here we call the 2 methods defined for our struct.
  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())
}