// Copyright © 2018 Inanc Gumus
// Learn Go Programming Course
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
//
// For more tutorials  : https://learngoprogramming.com
// In-person training  : https://www.linkedin.com/in/inancgumus/
// Follow me on twitter: https://twitter.com/inancgumus

package main

import (
	"fmt"
	"os"
	"strconv"
)

func main() {
	ships := []string{"Normandy", "Verrikan", "Nexus", "Warsaw"}

	fmt.Printf("%q\n\n", ships)

	from, to := 0, len(ships)

	switch poss := os.Args[1:]; len(poss) {
	default:
		fallthrough
	case 0:
		fmt.Println("Provide only the [starting] and [stopping] positions")
		return
	case 2:
		to, _ = strconv.Atoi(poss[1])
		fallthrough
	case 1:
		from, _ = strconv.Atoi(poss[0])
	}

	if l := len(ships); from < 0 || from > l || to > l || from > to {
		fmt.Println("Wrong positions")
		return
	}

	fmt.Println(ships[from:to])
}