package main

 import "fmt"

 func iMap(num []int, f func(a int) int) []int{

     var r []int

     for _, n := range num{

         r = append(r, f(n))

     }

     return r

 }

 func main() {

     num := []int{, , , }

     fmt.Println("before: ", num)

     result := iMap(num, func(a int) int{

         return a *

     })

     fmt.Println("after: ", result)

 }

before:  [   ]

after:  [   ]