App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 88 · 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 does this code show? (Positions start at 0.)
   let notes = ["Maths", "Music", "Hindi"];
   show(notes[0]); (a) Maths (b) Music (c) Hindi
2. 2.💾 Data saved only on the phone is lost when ___. (a) the app is closed (b) you send a message (c) the phone is lost (d) the screen turns off
3. 3.💾 Which works with no internet at all? (a) data saved on the phone (b) a cloud backup (c) a cloud leaderboard (d) a shared chat
4. 4.True or false: the sound on/off setting fits saving in the cloud. (a) True (b) False
5. 5.True or false: photos on two devices fits saving on the phone. (a) False (b) True
6. 6.💾 What number does this code show?
   let friends = ["Meera", "Riya", "Zoya"];
   friends.push("Kabir");
   show(friends.length);
7. 7.💾 What number does this code show?
   let notes = ["Maths", "Science"];
   notes.push("Art");
   show(notes.length);
8. 8.Which of these fits saving in the cloud? (a) notes to read offline (b) the sound on/off setting (c) a draft you are typing (d) chat messages to friends
9. 9.True or false: the sound on/off setting fits saving on the phone. (a) False (b) True
10. 10.💾 What does this code show? (Positions start at 0.)
    let friends = ["Kabir", "Meera", "Aman", "Riya"];
    show(friends[2]); (a) Kabir (b) Meera (c) Riya (d) Aman
11. 11.💾 pop() takes off the last item. What does this code show?
    let friends = ["Meera", "Kabir", "Zoya", "Riya"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Meera (b) Zoya (c) Kabir (d) Riya
12. 12.💾 Where should the app save your last game level: on the phone or in the cloud? (a) on the phone (b) in the cloud
13. 13.Which of these fits saving in the cloud? (a) your last game level (b) notes to read offline (c) photos on two devices (d) a draft you are typing
14. 14.💾 What does this code show? (Positions start at 0.)
    let notes = ["Sports", "Art", "Science", "Maths"];
    show(notes[3]); (a) Art (b) Science (c) Sports (d) Maths
15. 15.💾 What number does this code show?
    let friends = ["Arjun", "Aman", "Riya"];
    friends.push("Zoya");
    show(friends.length);
16. 16.💾 What number does this code show?
    let friends = ["Aman", "Zoya", "Meera"];
    friends.push("Riya");
    friends.push("Kabir");
    show(friends.length);
17. 17.💾 What does this code show? (Positions start at 0.)
    let songs = ["Monsoon", "Stars", "Sunrise", "Kites"];
    show(songs[3]); (a) Stars (b) Monsoon (c) Sunrise (d) Kites
18. 18.💾 What number does this code show?
    let notes = ["Art", "Science", "Hindi"];
    notes.push("Maths");
    notes.push("Sports");
    show(notes.length);
19. 19.Which of these fits saving in the cloud? (a) notes to read offline (b) a class leaderboard (c) a draft you are typing (d) the sound on/off setting
20. 20.True or false: a shared to-do list fits saving on the phone. (a) True (b) False
21. 21.💾 What number does this code show?
    let friends = ["Riya", "Meera", "Arjun"];
    friends.push("Aman");
    show(friends.length);
22. 22.True or false: chat messages to friends fits saving on the phone. (a) True (b) False
23. 23.💾 Where should the app save notes to read offline: on the phone or in the cloud? (a) in the cloud (b) on the phone
24. 24.💾 pop() takes off the last item. What does this code show?
    let songs = ["Ocean", "Monsoon", "Kites"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Kites (b) Ocean (c) Monsoon
25. 25.💾 What number does this code show?
    let points = 8;
    points = points - 2;
    points = points + 1;
    show(points);
26. 26.💾 Where should the app save a shared to-do list: on the phone or in the cloud? (a) on the phone (b) in the cloud
27. 27.Which of these fits saving on the phone? (a) a draft you are typing (b) a class leaderboard (c) chat messages to friends (d) a shared to-do list
28. 28.💾 What number does this code show?
    let notes = ["Science", "Maths", "Hindi", "Art"];
    notes.push("Sports");
    show(notes.length);
29. 29.True or false: photos on two devices fits saving in the cloud. (a) False (b) True
30. 30.💾 What number does this code show?
    let songs = ["Kites", "Monsoon", "Ocean", "Sunrise"];
    songs.push("Rain");
    songs.push("Stars");
    show(songs.length);
31. 31.True or false: a class leaderboard fits saving in the cloud. (a) False (b) True
32. 32.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) in the cloud (b) on the phone
33. 33.💾 pop() takes off the last item. What does this code show?
    let notes = ["Art", "Sports", "Music", "Science"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Science (b) Sports (c) Music (d) Art
34. 34.💾 In most code, the first item of a list is at position ___. (a) 10 (b) 2 (c) 1 (d) 0
35. 35.True or false: notes to read offline fits saving on the phone. (a) True (b) False
36. 36.Which of these fits saving on the phone? (a) photos on two devices (b) a class leaderboard (c) the sound on/off setting (d) a shared to-do list
37. 37.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) in the cloud (b) on the phone
38. 38.💾 What number does this code show?
    let notes = ["Music", "Maths"];
    notes.push("Sports");
    notes.push("Art");
    show(notes.length);
39. 39.💾 What does this code show? (Positions start at 0.)
    let notes = ["Science", "Sports", "Art", "Music"];
    show(notes[0]); (a) Music (b) Art (c) Sports (d) Science
40. 40.True or false: a shared to-do list fits saving in the cloud. (a) True (b) False

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