go_workshop/chapter_04/exercise_4.08/main.go

package main

import (
  "fmt"
  "os"
)

func getPassedArgs(minArgs int) []string {

  if len(os.Args) < minArgs {
    fmt.Printf("At least %v arguments are needed\n", minArgs)
    os.Exit(1)
  }

  var args []string
  for i := 1; i < len(os.Args); i++ {
    args = append(args, os.Args[i])
  }

  return args

}

func findLongest(args []string) string {

  var longest string
  for i := 0; i < len(args); i++ {
    if len(args[i]) > len(longest) {
      longest = args[i]
    }
  }

  return longest

}

func main() {

  if longest := findLongest(getPassedArgs(3)); len(longest) > 0 {
    fmt.Println("The longest word passed was:", longest)
  } else {
    fmt.Println("There was an error")
    os.Exit(1)
  }

}