type person struct{
        name string
        age int
}

var P person // P 現在就是 person 類型的變量了
P.name = "Astaxie" //  賦值 "Astaxie" 給 P 的 name 屬性 .
P.age = 25 //  賦值 "25" 給變量 P 的 age 屬性
fmt.Printf("The person's name is %s", P.name) //  訪問 P 的 name 屬性 .

P := person{"Liuxinming", 28}

P := person{age:28, name:"Liuxinming"}

package main

import "fmt"

//聲明一個新的類型
type person struct {
 name string
 avg  int
}

//比較兩個人的年齡，返回年齡大的那個人，并且返回年齡差
//struct 也是傳值的
func older(p1, p2 person) (person, int) {
 if p1.avg > p2.avg { //比較p1和p2年齡
  return p1, p1.avg - p2.avg
 }
 return p2, p2.avg - p1.avg
}

func main() {
 var tom person
 //賦值初始化
 tom.name, tom.avg = "Tom", 18

 //兩個字段都寫清楚的初始化
 bob := person{avg: 25, name: "Bob"}

 //按照struct定義順序初始化
 paul := person{"Paul", 43}

 tb_Older, tb_diff := older(tom, bob)
 tp_Older, tp_diff := older(tom, paul)
 bp_Older, bp_diff := older(bob, paul)

 fmt.Printf("Of %s and %s, %s is older by %d years\n",
  tom.name, bob.name, tb_Older.name, tb_diff)
 fmt.Printf("Of %s and %s, %s is older by %d years\n",
  tom.name, paul.name, tp_Older.name, tp_diff)
 fmt.Printf("Of %s and %s, %s is older by %d years\n",
  bob.name, paul.name, bp_Older.name, bp_diff)
}

Of Tom and Bob, Bob is older by 7 years
Of Tom and Paul, Paul is older by 25 years
Of Bob and Paul, Paul is older by 18 years

// struct2.go
package main

import (
 "fmt"
)

type Human struct {
 name   string
 age    int
 weight int
}
type Student struct {
 Human      //匿名字段，那么默認struct就包含了Human所有字段
 speciality string
}

func main() {
 //初始化一個學生
 mark := Student{Human{"Mark", 25, 100}, "Computer Science"}

 //訪問相應的字段
 fmt.Println("His name is ", mark.name)
 fmt.Println("His age is ", mark.age)
 fmt.Println("His weight is ", mark.weight)
 fmt.Println("His speciality is ", mark.speciality)

 //修改對應的信息
 mark.speciality = "AI"
 fmt.Println("Mark changed his speciality")
 fmt.Println("His speciality is ", mark.speciality)
 //  修改他的年齡信息
 fmt.Println("Mark become old")
 mark.age = 46
 fmt.Println("His age is", mark.age)
 //  修改他的體重信息
 fmt.Println("Mark is not an athlet anymore")
 mark.weight += 60
 fmt.Println("His weight is", mark.weight)
}

His name is  Mark
His age is  25
His weight is  100
His speciality is  Computer Science
Mark changed his speciality
His speciality is  AI
Mark become old
His age is 46
Mark is not an athlet anymore
His weight is 160