Interface example

interface.go

package main

// Dog struct
type Dog struct{}

// Speak is receiver method for how the dog speak
func (d *Dog) Speak() string {
	return "woof"
}

// Animal interface that going to consume the type Dog implementation
type Animal interface {
	Speak() string
}

func main() {
	var a Animal
	a = &Dog{}

	fmt.Println(a.Speak())
}