``` package main import ( "fmt" ) // 封裝和繼承：通過結構體和嵌套結構體實現 type Animal struct { Name string } func (a *Animal) Speak() { fmt.Printf("%s makes a sound\n", a.Name) } type Dog struct { Animal // 嵌套Animal結構體，實現繼承 Breed string } func (d *Dog) Speak() { fmt.Printf("%s barks: Woof Woof!\n", d.Name) } type Cat struct { Animal // 嵌套Animal結構體，實現繼承 Breed string } func (c *Cat) Speak() { fmt.Printf("%s meows: Meow Meow!\n", c.Name) } // 多態：通過接口實現 type Speaker interface { Speak() } func LetAnimalSpeak(speaker Speaker) { speaker.Speak() } func main() { // 創建Dog和Cat對象 dog := Dog{Animal{"Rover"}, "Golden Retriever"} cat := Cat{Animal{"Whiskers"}, "Siamese"} // 使用多態 LetAnimalSpeak(&dog) // 多態，調用Dog的Speak方法 LetAnimalSpeak(&cat) // 多態，調用Cat的Speak方法 } ```