go-struct嵌套和继承

一、结构体嵌套

package main

import "fmt"

type Student struct {
    Name string
    Age int
    Score int
}

func (stu *Student) ShowInfo() {
    fmt.Printf("学生名＝%v 年龄= %v 成绩=%v\n", stu.Name, stu.Age, stu.Score)
}

func (stu *Student) SetScore(score int) {
    stu.Score = score
}

type Pupil struct {
    Student
}

func (p *Pupil) testing() {
    fmt.Println("小学生正在考试中")
}

type Graduate struct {
    Student
}

func (p *Graduate) testing() {
    fmt.Println("DA学生正在考试中")
}
func main()  {

    var pupil = &Pupil{}
    pupil.Student.Name = "tom"
    pupil.Student.Age = 8
    pupil.testing()
    pupil.Student.SetScore(30)
    pupil.Student.ShowInfo()

    var granduate = &Graduate{}
    granduate.Student.Name = "w"
    granduate.Student.Age =20
    granduate.testing()
    granduate.Student.SetScore(3)
    granduate.Student.ShowInfo()
}
运行结果：
小学生正在考试中
学生名＝tom 年龄= 8 成绩=30
DA学生正在考试中
学生名＝w 年龄= 20 成绩=3

无论大学生小学生都有年龄和分数，不一样的就是testing()方法是大学生、小学生在考试，所以单独用Pupil和Graduate指针去接收，ShowInfo()和SetScore()用student指针去接收

二、继承

好处：复用性、维护性、扩展性

type Animal struct {
    Name string
    age int
}
func (animal *Animal) SayOk() {
    fmt.Println("animal say", animal.Name)
}
func (animal *Animal) hello() {
    fmt.Println("animal hello", animal.Name)
}
type Dog struct {
    Animal
}
func main()  {
    var dog Dog
    dog.Animal.Name = "哈市　dog"
    dog.Animal.age = 20
    dog.Animal.SayOk()
    dog.Animal.hello()
    dog.Name = "后代dog"
    dog.age = 1
    dog.SayOk()
    dog.hello()
}
运行结果：
animal say 哈市　dog
animal hello 哈市　dog
animal say 后代dog
animal hello 后代dog

1.直接访问dog的字段或者方法,dog.Name
2.编译的时候会先看dog对应的有没有Name，如果有则直接滴啊用dog类型的Name,如果没有就去看animal的结构体中有没有这个字段
3.当结构体和匿名结构体都有相同的字段和方法，采用就近原则，如果要指定那就指定一下

type Animal struct {
    Name string
    age int
}
func (animal *Animal) SayOk() {
    fmt.Println("animal say", animal.Name)
}
func (animal *Animal) hello() {
    fmt.Println("animal hello", animal.Name)
}
type Dog struct {
    Animal
    Name string
}
func (dog *Dog) hello() {
    fmt.Println("dog hello", dog.Name)
}
func main()  {
    var dog Dog
    dog.Animal.Name = "哈市　dog"
    dog.Name = "后代dog"
    dog.Animal.age = 20
    dog.Animal.SayOk()
    dog.Animal.hello()
    dog.age = 1
    dog.SayOk()
    dog.hello()
}
运行结果：
animal say 哈市　dog
animal hello 哈市　dog
animal say 哈市　dog
dog hello 后代dog

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