Go 接口

package main
//接口，换个角度看世界

import "fmt"

type Human struct {
    name string
    age int
    phone string
}

type Student struct {
    Human //匿名字段
    school string
    loan float32
}

type Employee struct {
    Human //匿名字段
    company string
    money 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，后两个是通过继承
type Men interface {
    SayHi()
    Sing(lyrics string)
}

func main() {
    mike := Student{Human{"Mike", 25, "222-222-XXX"}, "MIT", 0.00}  //结构体的声明
    paul := Student{Human{"Paul", 26, "111-222-XXX"}, "Harvard", 100}
    sam := Employee{Human{"Sam", 36, "444-222-XXX"}, "Golang Inc.", 1000}
    tom := Employee{Human{"Tom", 37, "222-444-XXX"}, "Things Ltd.", 5000}

    //定义Men类型的变量i
    var i Men

    //i能存储Student
    i = mike
    fmt.Println("This is Mike, a Student:")
    i.SayHi()
    i.Sing("November rain")

    //i也能存储Employee
    i = tom
    fmt.Println("This is tom, an Employee:")
    i.SayHi()
    i.Sing("Born to be wild")

    //定义了slice Men
    fmt.Println("Let's use a slice of Men and see what happens")
    x := make([]Men, 3)  //分配3个lens
    //这三个都是不同类型的元素，但是他们实现了interface同一个接口
    x[0], x[1], x[2] = paul, sam, mike

    for _, value := range x{
        value.SayHi()
    }
    // Go通过interface实现了duck-typing:
    // 即"当看到一只鸟走起来像鸭子、游泳起来像鸭子、叫起来也像鸭子，那么这只鸟就可以被称为鸭子"。
}