interfaces

main.go

package main

import "fmt"

type animal interface {
	Run() string
}

type dog struct {
	Name string
}

type cat struct {
	Name string
}

func (d dog) Run() string {
	return "running " + d.Name
}

func (c cat) Run() string {
	return "running " + c.Name
}

func main() {
	testrun(dog{Name: "Lassy"})
	testrun(cat{Name: "Kitty"})
}

func testrun(a animal) {
	fmt.Print(a.Run())
}