递归函数

func sum(x int) int {
   z:= x * 3
   if(z < 100){
      return sum(z)
   }
   return z
}

func main()  {
   fmt.Println(sum(5))
}

类型别名/自定义类型

//自定义类型
type int64 int
//类型别名
type int128 =  int
func main()  {
   var a int64 = 65
   fmt.Println(a)
   fmt.Printf("%T \n",a)

   var b int128 = 65
   fmt.Println(b)
   fmt.Printf("%T \n",b)

   var c rune
   c = 12
   fmt.Println(c)
   fmt.Printf("%T \n",c)
}

 结构体

type person struct {
   name string
   age int
   gender string
   hobby []string
}

func main()  {
   var p person
   p.name = ""
   p.age = 12
   p.hobby = []string{}

   fmt.Printf("%#v\n",p)

   //匿名结构体
   var s struct{
      x int
      y string
   }
   s.x = 1
   fmt.Printf("%#v\n",s)

}

结构体操作

type dog struct {
   name string
}

func (d dog) dogs()  {
   fmt.Println(d.name)
}

type myint int

func (i myint) mynum()  {
   fmt.Println(i)
}

func main()  {
   d := dog{name:"狗"}
   d.dogs()

   i := myint(123)
i = 789
   i.mynum()
}

嵌套

//嵌套
type A struct {
   name string
}

type B struct {
   age int
}

type C struct {
   names A
   B
}


func main()  {

   var p C
   p.names.name = "ads"
   p.age = 12

   fmt.Printf("%v\n", p)
   fmt.Printf("%#v\n", p)

   d := C{names:A{name:"asd"},B:B{age:111}}
   fmt.Printf("%v\n", d)
   fmt.Printf("%#v\n", d)

}

结构体继承

type animal struct {
   name string
}

func (a animal) move()  {
   fmt.Printf("%s 会动 \n",a.name)
}

type dog struct {
   feet uint8
   animal
}

func (d dog) wang()  {
   fmt.Printf("%s 会  汪汪汪~~~ \n",d.name)
}

func main()  {
   gou := dog{feet:111,animal:animal{name:"大狗"}}
   gou.move()
   gou.wang()
}

结构体与json

//结构体与json
//1. 序列化  结构体转为json
//2. 反序列化  json转go的结构体

type status struct {
   Name string `json:"name"`
   Age int `json:"age"`
   Money float64 `json:"money"`
}

func main()  {
   j := status{
      Name:  "张三",
      Age:   0,
      Money: 0,
   }


   //返回的是字节
   js,err := json.Marshal(j) ;if err!=nil{
      fmt.Println("报错了")
   }
   //需要转一下
   jsons :=string(js)
   fmt.Println("json: ",jsons)

   //反序列化
   var p status
   json.Unmarshal([]byte(jsons),&p)
   fmt.Printf("%#v \n",p)
}

练习操作

package main

import "fmt"

type class struct {
   id int
   title string
}

type school struct {
   cls map[int]class
}

func (sch *school) addclass(id int,title string)  {
   c := class{
      id:    id,
      title: title,
   }
   if sch.cls == nil {
      sch.cls = make(map[int]class)
   }
   key := len(sch.cls)+1
   sch.cls[key] = c
}

func main()  {

   var sch school
   sch.addclass(1001,"高二三班")
   sch.addclass(1002,"高二四班")
   sch.addclass(1003,"高二一班")
   sch.addclass(1004,"高二二班")


   fmt.Println(sch)
}