Golang通脉之方法详情

func (t Type) methodName(parameter)(return) {
  
}

//Person 结构体
type Person struct {
 name string
 age  int8
}
 
//NewPerson 构造函数
func NewPerson(name string, age int8) *Person {
 return &Person{
  name: name,
  age:  age,
 }
}
 
//Dream Person做梦的方法
func (p Person) Dream() {
 fmt.Printf("%s的梦想是学好Go语言！\n", p.name)
}
 
func main() {
 p1 := NewPerson("张三", 25)
 p1.Dream()
}

type Rectangle struct {
 width, height float64
}
type Circle struct {
 radius float64
}
 
 
func (r Rectangle) area() float64 {
 return r.width * r.height
}
//该 method 属于 Circle 类型对象中的方法
func (c Circle) area() float64 {
 return c.radius * c.radius * math.Pi
}
func main() {
 r1 := Rectangle{12, 2}
 r2 := Rectangle{9, 4}
 c1 := Circle{10}
 c2 := Circle{25}
 fmt.Println("Area of r1 is: ", r1.area())
 fmt.Println("Area of r2 is: ", r2.area())
 fmt.Println("Area of c1 is: ", c1.area())
 fmt.Println("Area of c2 is: ", c2.area())
}

type Rectangle struct {
 width, height int
}
 
func (r *Rectangle) setVal() {
 r.height = 20
}
 
func main() {
 p := Rectangle{1, 2}
 s := p
 p.setVal()
 fmt.Println(p.height, s.height)
}

type Rectangle struct {
 width, height int
}
 
func (r Rectangle) setVal() {
 r.height = 20
}
 
func main() {
 p := Rectangle{1, 2}
 s := p
 p.setVal()
 fmt.Println(p.height, s.height)  // 2 2
}

type Employee struct {  
    name     string
    salary   int
    currency string
}
 

func displaySalary(e Employee) {  
    fmt.Printf("Salary of %s is %s%d", e.name, e.currency, e.salary)
}
 
func main() {  
    emp1 := Employee{
        name:     "Sam Adolf",
        salary:   5000,
        currency: "$",
    }
    displaySalary(emp1)
}

//MyInt 将int定义为自定义MyInt类型
type MyInt int
 
//SayHello 为MyInt添加一个SayHello的方法
func (m MyInt) SayHello() {
 fmt.Println("Hello, 我是一个int。")
}
func main() {
 var m1 MyInt
 m1.SayHello() //Hello, 我是一个int。
 m1 = 100
 fmt.Printf("%#v  %T\n", m1, m1) //100  main.MyInt
}

type Human struct {
 name  string
 age   int
 phone string
}
type Student struct {
 Human  //匿名字段
 school string
}
type Employee struct {
 Human   //匿名字段
 company string
}
 
func (h *Human) SayHi() {
 fmt.Printf("Hi, I am %s you can call me on %s\n", h.name, h.phone)
}
func main() {
 mark := Student{Human{"Mark", 25, "222-222-YYYY"}, "MIT"}
 sam := Employee{Human{"Sam", 45, "111-888-XXXX"}, "golang Inc"}
 mark.SayHi()
 sam.SayHi()
}

Hi, I am Mark you can call me on 222-222-YYYY
Hi, I am Sam you can call me on 111-888-XXXX

type Human struct {
 name  string
 age   int
 phone string
}
type Student struct {
 Human  //匿名字段
 school string
}
type Employee struct {
 Human   //匿名字段
 company string
}
 
//Human定义method
func (h *Human) SayHi() {
 fmt.Printf("Hi, I am %s you can call me on %s\n", h.name, h.phone)
}
 
//Employee的method重写Human的method
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) //Yes you can split into 2 lines here.
}
func main() {
 mark := Student{Human{"Mark", 25, "222-222-YYYY"}, "MIT"}
 sam := Employee{Human{"Sam", 45, "111-888-XXXX"}, "Golang Inc"}
 mark.SayHi()
 sam.SayHi()
}

type Person struct {
 name   string
 age    int8
 dreams []string
}
 
func (p *Person) SetDreams(dreams []string) {
 p.dreams = dreams
}
 
func main() {
 p1 := Person{name: "张三", age: 18}
 data := []string{"吃饭", "睡觉", "打豆豆"}
 fmt.Printf("%p\n",data)  //0xc00006e360
 p1.SetDreams(data)      //传的是 data 的内存地址，此时p.dreams和data指向同一块内存空间
 fmt.Printf("%p\n",p1.dreams) //0xc00006e360
 
 // 你真的想要修改 p1.dreams 吗？
 data[1] = "不睡觉"    //data值的修改会影响person结构体的dream字段
 fmt.Println(p1.dreams)  // [吃饭 不睡觉 打豆豆]
}

func (p *Person) SetDreams(dreams []string) {
 p.dreams = make([]string, len(dreams))
 copy(p.dreams, dreams)
}