go类型的默认值，注意pointer, channel, func, interface, map, or slice在没初始化的情况下

nil is a predeclared identifier representing the zero value for a pointer, channel, func, interface, map, or slice type.
Type must be a pointer, channel, func, interface, map, or slice type

package main

import "fmt"



func main() {
   var slic []string
   var m map[string]interface{}
   var i interface{}
   var ptr *int
   var c chan string
   var f func()
   var s *struct{}
   fmt.Println(slic,m,i,ptr,c,f,s)
   if slic == nil{
      fmt.Println("true")
   }
   if m == nil{
      fmt.Println("true")
   }


}
//reset

[] map[] <nil> <nil> <nil> <nil> <nil>
true
true

进程 已完成，退出代码为 0