74 lines
2.0 KiB
Go
74 lines
2.0 KiB
Go
|
// For more tutorials: https://blog.learngoprogramming.com
|
||
|
|
//
|
||
|
|
// Copyright © 2018 Inanc Gumus
|
||
|
|
// Learn Go Programming Course
|
||
|
|
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
|
||
|
|
//
|
||
|
|
|
||
|
|
package main
|
||
|
|
|
||
|
|
import (
|
||
|
|
"fmt"
|
||
|
|
|
||
|
|
"github.com/inancgumus/learngo/16-slices/exercises/19-limit-the-backing-array-sharing/api"
|
||
|
|
)
|
||
|
|
|
||
|
|
// ---------------------------------------------------------
|
||
|
|
// EXERCISE: Limit the backing array sharing
|
||
|
|
//
|
||
|
|
// You've created an API that returns population counts in a country.
|
||
|
|
// To do that, you return an int slice up to some portion of it.
|
||
|
|
//
|
||
|
|
// There is a program that uses your API but it appends to the slice
|
||
|
|
// that your API returns. Doing so, overwrites your API's slice's
|
||
|
|
// backing array as well.
|
||
|
|
//
|
||
|
|
// Change your API so that it prevents the overwriting when
|
||
|
|
// the client code wants to append to the returned slice from your
|
||
|
|
// API.
|
||
|
|
//
|
||
|
|
//
|
||
|
|
// STEPS
|
||
|
|
//
|
||
|
|
// 1. Open the code inside the `api/api.go` folder
|
||
|
|
//
|
||
|
|
// 2. Fix the code there (not here — but run this code after)
|
||
|
|
//
|
||
|
|
//
|
||
|
|
// CURRENT OUTPUT
|
||
|
|
//
|
||
|
|
// The following program overwrites the elements incorrectly
|
||
|
|
// You need to change your API to prevent this behavior
|
||
|
|
// ^ ^
|
||
|
|
// | |
|
||
|
|
// API's readings: [5 10 3 1 3 80 90]
|
||
|
|
// Your readings : [5 10 3 1 3]
|
||
|
|
//
|
||
|
|
//
|
||
|
|
// EXPECTED OUTPUT
|
||
|
|
//
|
||
|
|
// Now the program cannot change the API's original backing array
|
||
|
|
// (beyond the returned capacity) (so the api now owns the control)
|
||
|
|
// ^ ^
|
||
|
|
// | |
|
||
|
|
// API's readings: [5 10 3 25 45 80 90]
|
||
|
|
// Your readings : [5 10 3 1 3]
|
||
|
|
//
|
||
|
|
// ---------------------------------------------------------
|
||
|
|
|
||
|
|
func main() {
|
||
|
|
// DO NOT TOUCH THE FOLLOWING CODE
|
||
|
|
// THIS IS THE CLIENT PROGRAM THAT USES YOUR API
|
||
|
|
// YOU CANNOT CONTROL IT! :)
|
||
|
|
|
||
|
|
// reads the first three temperatures
|
||
|
|
temps := api.Read(0, 3)
|
||
|
|
|
||
|
|
// appends two new temperature readings
|
||
|
|
temps = append(temps, []int{1, 3}...)
|
||
|
|
|
||
|
|
// prints the current temperatures
|
||
|
|
fmt.Println("API's readings:", api.All())
|
||
|
|
fmt.Println("Your readings :", temps)
|
||
|
|
}
|