App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 340 · 40 questions

Developer's tip (Box, list, place): A variable holds one value; a list holds many in order. Positions start at 0. push adds to the end; pop takes off the last item; length is how many items. On the phone: works offline, private. In the cloud: shared, any device, needs the internet.

1. 1.💾 What number does this code show?
   let notes = ["Music", "Sports", "Science", "Maths"];
   notes.push("Art");
   show(notes.length);
2. 2.💾 pop() takes off the last item. What does this code show?
   let songs = ["Kites", "Ocean", "Stars", "Monsoon"];
   songs.pop();
   show(songs[songs.length - 1]); (a) Monsoon (b) Stars (c) Ocean (d) Kites
3. 3.💾 pop() takes off the last item. What does this code show?
   let notes = ["Sports", "Hindi", "Music"];
   notes.pop();
   show(notes[notes.length - 1]); (a) Music (b) Hindi (c) Sports
4. 4.💾 Where should the app save your last game level: on the phone or in the cloud? (a) in the cloud (b) on the phone
5. 5.💾 What does this code show? (Positions start at 0.)
   let friends = ["Riya", "Kabir", "Arjun"];
   show(friends[1]); (a) Kabir (b) Arjun (c) Riya
6. 6.💾 What does this code show? (Positions start at 0.)
   let songs = ["Rain", "Kites", "Ocean", "Sunrise", "Stars"];
   show(songs[3]); (a) Kites (b) Ocean (c) Rain (d) Sunrise
7. 7.💾 Data saved only on the phone is lost when ___. (a) you send a message (b) the screen turns off (c) the phone is lost (d) the app is closed
8. 8.💾 What number does this code show?
   let friends = ["Aman", "Arjun", "Zoya"];
   friends.push("Meera");
   friends.push("Riya");
   show(friends.length);
9. 9.True or false: chat messages to friends fits saving on the phone. (a) False (b) True
10. 10.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) in the cloud (b) on the phone
11. 11.Which of these fits saving in the cloud? (a) a draft you are typing (b) your last game level (c) the sound on/off setting (d) a class leaderboard
12. 12.💾 What number does this code show?
    let friends = ["Zoya", "Aman"];
    friends.push("Kabir");
    show(friends.length);
13. 13.💾 What number does this code show?
    let notes = ["Music", "Art"];
    notes.push("Hindi");
    show(notes.length);
14. 14.True or false: a class leaderboard fits saving in the cloud. (a) False (b) True
15. 15.💾 Saving data in the cloud lets you ___. (a) skip the internet (b) use it on any device (c) never need a password (d) shrink the app
16. 16.True or false: a shared to-do list fits saving on the phone. (a) True (b) False
17. 17.💾 What number does this code show?
    let friends = ["Meera", "Aman"];
    friends.push("Arjun");
    friends.push("Kabir");
    show(friends.length);
18. 18.💾 Where should the app save a draft you are typing: on the phone or in the cloud? (a) in the cloud (b) on the phone
19. 19.True or false: notes to read offline fits saving in the cloud. (a) False (b) True
20. 20.True or false: a class leaderboard fits saving on the phone. (a) True (b) False
21. 21.Which of these fits saving on the phone? (a) a shared to-do list (b) photos on two devices (c) your last game level (d) a class leaderboard
22. 22.💾 pop() takes off the last item. What does this code show?
    let songs = ["Stars", "Rain", "Ocean", "Sunrise"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Sunrise (b) Stars (c) Ocean (d) Rain
23. 23.💾 Which works with no internet at all? (a) a cloud leaderboard (b) a cloud backup (c) data saved on the phone (d) a shared chat
24. 24.Which of these fits saving on the phone? (a) photos on two devices (b) the sound on/off setting (c) a shared to-do list (d) chat messages to friends
25. 25.💾 What is a variable? (a) a picture (b) a type of screen (c) a named box for a value (d) a phone setting
26. 26.True or false: your last game level fits saving in the cloud. (a) True (b) False
27. 27.💾 What number does this code show?
    let notes = ["Hindi", "Art"];
    notes.push("Sports");
    notes.push("Science");
    show(notes.length);
28. 28.💾 What number does this code show?
    let friends = ["Meera", "Zoya"];
    friends.push("Aman");
    friends.push("Riya");
    show(friends.length);
29. 29.Which of these fits saving on the phone? (a) a class leaderboard (b) photos on two devices (c) notes to read offline (d) a shared to-do list
30. 30.💾 What number does this code show?
    let points = 7;
    points = points - 4;
    points = points + 1;
    show(points);
31. 31.True or false: the sound on/off setting fits saving on the phone. (a) False (b) True
32. 32.💾 What number does this code show?
    let notes = ["Science", "Hindi", "Music"];
    notes.push("Art");
    notes.push("Sports");
    show(notes.length);
33. 33.Which of these fits saving in the cloud? (a) the sound on/off setting (b) chat messages to friends (c) a draft you are typing (d) notes to read offline
34. 34.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) on the phone (b) in the cloud
35. 35.💾 Where should the app save a shared to-do list: on the phone or in the cloud? (a) in the cloud (b) on the phone
36. 36.True or false: your last game level fits saving on the phone. (a) False (b) True
37. 37.💾 What number does this code show?
    let coins = 8;
    coins = coins - 3;
    coins = coins + 1;
    show(coins);
38. 38.💾 What number does this code show?
    let songs = ["Rain", "Sunrise", "Ocean"];
    songs.push("Stars");
    show(songs.length);
39. 39.💾 What number does this code show?
    let songs = ["Rain", "Monsoon"];
    songs.push("Stars");
    songs.push("Ocean");
    show(songs.length);
40. 40.💾 What number does this code show?
    let stars = 9;
    stars = stars - 6;
    stars = stars + 4;
    show(stars);

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