ff1.go

type Car interface {
  Drive() string
}

type SportsCar struct {}

func (s SportsCar) Drive() string {
  return "Vroom vroom!"
}

type SUV struct {}

func (s SUV) Drive() string {
  return "Rumble rumble!"
}

func NewCar(carType string) Car {
    if carType == "sports" {
        return SportsCar{}
    } else if carType == "suv" {
        return SUV{}
    }
    return nil
}

myCar := NewCar("sports")
fmt.Println(myCar.Drive())
// Output: Vroom vroom!