golang常見錯誤

import

import unuse package:error : imported and not used: "os" 

:= =

c := 1 // error non-declaration statement outside function bodyd = 1 // error non-declaration statement outside function body

func test(){
c = 1 //undefined: should be c:=1
//d = 1
var f , d int
f,d = cal()
fmt.Println(c, f, d)
}

right using value declare and use

package mainimport "fmt"//var a := 0 //wrongvar a int = 0//c := 1 //wrong//d = 1 //wrongfunc cal(b int)(val1 int, val2 int){  fmt.Println(b)  val1 = 1  val2 = 2  return }func test(){  c := 1  //d = 1 //wrong  var f , d int  f,d = cal(1)  fmt.Println(c, f, d)}func main() {  fmt.Println("Hello, world var")}

declear not use

./right.go:14: c declared and not used  

type struct init using () ,instead of {} ,which {} is the right usage

type Response struct {  Code string `json:"code"`  Body string `json:"body"`}//not like this ()//Response("OK", "ECHO: " + method + " ~ " + params)//right usage {}Response{"OK", "ECHO: " + method + " ~ " + params}

如何理解以下代碼：

type IpcClient struct {  conn chan string}func (client *IpcClient)Call(method, params string)(resp *Response, err error){  }

• (client *IpcClient) -- 調用的對象要是 IpcClient struct
  
• (method, params string) -- 參數，前面是參數名，後面是參數類型，兩種同類別省略寫法。
• (resp *Response, err error) 參數傳回值，傳回值的第一個參數，類型為 Response struct 對象指標, 傳回值的第二個參數，類型為 error 類型,

wrong not using go keyworld when call async func