struct匿名字段和interface，断言

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// 定义interfacetype Men interface {SayHi()Sing(lyrics string)}type Human struct {name stringage intphone string} type Student struct {Human //匿名字段school stringloan float32}//Human实现SayHi方法func (h Human) SayHi() {fmt.Printf("Hi, I am %s you can call me on %s\n", h.name, h.phone)}

//Human实现Sing方法func (h Human) Sing(lyrics string) {fmt.Println("La la la la...", lyrics)} //Employee重载Human的SayHi方法func (e Employee) SayHi() {fmt.Printf("Hi, I am %s, I work at %s. Call me on %s\n", e.name,e.company, e.phone)}

Interface Men被Human,Student和Employee实现，
因为这三个类型都实现了这两个方法，Interface Men的值可以是实现了该接口的任一对象。任何对象只要定义了String方法，都可以用Printf输出函数输出，如下：

type Element interface{}type List [] Elementtype Person struct {name stringage int}

//定义了String方法，实现了fmt.Stringerfunc (p Person) String() string {return "(name: " + p.name + " - age: "+strconv.Itoa(p.age)+ " years)"}

func main() {list := make(List, 3)list[0] = 1 // an intlist[1] = "Hello" // a stringlist[2] = Person{"Dennis", 70}

// Go语言里面有一个语法，可以直接判断某个接口是否是该类型的变量(断言assert interface.(type))

// value, ok = element.(T)for index, element := range list {if value, ok := element.(int); ok {fmt.Printf("list[%d] is an int and its value is %d\n", index, value)} else if value, ok := element.(string); ok {fmt.Printf("list[%d] is a string and its value is %s\n", index, value)} else if value, ok := element.(Person); ok {fmt.Printf("list[%d] is a Person and its value is %s\n", index, value)} else {fmt.Printf("list[%d] is of a different type\n", index)}}}

//另外一种使用switch的用法:

for index, element := range list{switch value := element.(type) {case int:fmt.Printf("list[%d] is an int and its value is %d\n", index,case string:fmt.Printf("list[%d] is a string and its value is %s\n", indecase Person:fmt.Printf("list[%d] is a Person and its value is %s\n", indedefault:fmt.Println("list[%d] is of a different type", index)}}

//嵌入interface，类似匿名字段

// io.ReadWriter可以使用Reader和Writer中的所有方法type ReadWriter interface {ReaderWriter}

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