Understanding interfaces in Golang - function

Question

I'm trying to understand interfaces in Go. I wrote this:
package main
import "fmt"
type Animal struct {
Name string
Ability string
}
type AbilityShower interface {
ShowAbility() string
}
func (a Animal) ShowAbility() string {
return fmt.Sprintf("%s can %s", a.Name, a.Ability)
}
func main() {
var Dog Animal = Animal{
Name: "Dog",
Ability: "Walk",
}
Dog.ShowAbility()
}
But when I run with go run main.go nothing appears in the console. What am I doing incorrectly?

Answer 1

You are not printing the result. Change the main to
func main() {
var Dog Animal = Animal{
Name: "Dog",
Ability: "Walk",
}
fmt.Println(Dog.ShowAbility())
}
FYI: fmt.Sprintf() returns a string and doesn't print it to standard output
// Sprintf formats according to a format specifier and returns the
resulting string.

Answer 2

You are returning a string from the ShowAbility method, but not outputting it.
package main
import "fmt"
type Animal struct {
Name string
Ability string
}
type AbilityShower interface {
ShowAbility()
}
func (a Animal) ShowAbility() {
fmt.Printf("%s can %s", a.Name, a.Ability)
}
func main() {
var Dog Animal = Animal{
Name: "Dog",
Ability: "Walk",
}
Dog.ShowAbility()
}

Answer 3

Here you are using fmt.Sprintf which actually works like Scanf returning value. You need to assign that value to a variable and print the output.
func main() {
var Dog Animal = Animal{
Name: "Dog",
Ability: "Walk",
}
output := Dog.ShowAbility()
fmt.Println(output)
}
If you wants to print when calling the function ShowAbility() you can use Printf function of fmt package.
func (a Animal) ShowAbility() {
fmt.Printf("%s can %s", a.Name, a.Ability)
}
func main() {
var Dog Animal = Animal{
Name: "Dog",
Ability: "Walk",
}
Dog.ShowAbility()
}