1、接口的定义和实现以及接口的继承
示例：
package main import "fmt" //定义接口类型
type Humaner interface {
//方法，只有声明，没有实现，由别的类型（自定义类型）实现
sayhi()
} type Student struct {
name string
id int
} //Student实现了此方法
func (tmp *Student) sayhi() {
fmt.Printf("Student[%s, %d] sayhi\n", tmp.name, tmp.id)
} type Teacher struct {
addr string
group string
} //Teacher实现了此方法
func (tmp *Teacher) sayhi() {
fmt.Printf("Teacher[%s, %s] sayhi\n", tmp.addr, tmp.group)
} type MyStr string //MyStr实现了此方法
func (tmp *MyStr) sayhi() {
fmt.Printf("MyStr[%s] sayhi\n", *tmp)
} //定义一个普通函数，函数的参数为接口类型
//只有一个函数，可以有不同表现，多态
func WhoSayHi(i Humaner) {
i.sayhi()
} func main() {
s := &Student{"mike", 666}
t := &Teacher{"bj", "go"}
var str MyStr = "hello mike" //调用同一函数，不同表现，多态，多种形态
WhoSayHi(s)
WhoSayHi(t)
WhoSayHi(&str) //创建一个切片
x := make([]Humaner, 3)
x[0] = s
x[1] = t
x[2] = &str //第一个返回下标，第二个返回下标所对应的值
for _, i := range x {
i.sayhi()
} } func main01() {
//定义接口类型的变量
var i Humaner //只是实现了此接口方法的类型，那么这个类型的变量（接收者类型）就可以给i赋值
s := &Student{"mike", 666}
i = s
i.sayhi() t := &Teacher{"bj", "go"}
i = t
i.sayhi() var str MyStr = "hello mike"
i = &str
i.sayhi() }
#执行结果：
Student[mike, 666] sayhi
Teacher[bj, go] sayhi
MyStr[hello mike] sayhi Student[mike, 666] sayhi
Teacher[bj, go] sayhi
MyStr[hello mike] sayhi