Method area

examples/interfaces/interfaces.go:29–31

To implement an interface in Go, we just need to implement all the methods in the interface. Here we implement `geometry` on `rect`s.

()

// implement all the methods in the interface. Here we
// implement `geometry` on `rect`s.
func (r rect) area() float64 {
	return r.width * r.height
}
func (r rect) perim() float64 {
	return 2*r.width + 2*r.height
}