App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 525 · 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.💾 In most code, the first item of a list is at position ___. (a) 2 (b) 10 (c) 1 (d) 0
2. 2.💾 pop() takes off the last item. What does this code show?
   let notes = ["Art", "Hindi", "Science"];
   notes.pop();
   show(notes[notes.length - 1]); (a) Art (b) Science (c) Hindi
3. 3.True or false: the sound on/off setting fits saving on the phone. (a) True (b) False
4. 4.💾 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
5. 5.💾 Saving data in the cloud lets you ___. (a) never need a password (b) skip the internet (c) use it on any device (d) shrink the app
6. 6.True or false: your last game level fits saving on the phone. (a) True (b) False
7. 7.True or false: a draft you are typing fits saving in the cloud. (a) True (b) False
8. 8.Which of these fits saving in the cloud? (a) your last game level (b) a draft you are typing (c) the sound on/off setting (d) a shared to-do list
9. 9.💾 Which works with no internet at all? (a) a shared chat (b) a cloud leaderboard (c) a cloud backup (d) data saved on the phone
10. 10.💾 What does this code show? (Positions start at 0.)
    let friends = ["Arjun", "Riya", "Zoya", "Kabir"];
    show(friends[0]); (a) Kabir (b) Arjun (c) Zoya (d) Riya
11. 11.True or false: a draft you are typing fits saving on the phone. (a) False (b) True
12. 12.Which of these fits saving on the phone? (a) photos on two devices (b) a shared to-do list (c) a class leaderboard (d) notes to read offline
13. 13.💾 What number does this code show?
    let songs = ["Kites", "Rain", "Sunrise"];
    songs.push("Monsoon");
    show(songs.length);
14. 14.💾 Where should the app save the sound on/off setting: on the phone or in the cloud? (a) on the phone (b) in the cloud
15. 15.True or false: notes to read offline fits saving in the cloud. (a) True (b) False
16. 16.True or false: the sound on/off setting fits saving in the cloud. (a) False (b) True
17. 17.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) in the cloud (b) on the phone
18. 18.💾 What number does this code show?
    let friends = ["Zoya", "Arjun", "Kabir", "Meera"];
    friends.push("Aman");
    friends.push("Riya");
    show(friends.length);
19. 19.💾 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
20. 20.💾 Data saved only on the phone is lost when ___. (a) the phone is lost (b) you send a message (c) the screen turns off (d) the app is closed
21. 21.Which of these fits saving in the cloud? (a) your last game level (b) chat messages to friends (c) a draft you are typing (d) the sound on/off setting
22. 22.💾 What number does this code show?
    let songs = ["Sunrise", "Monsoon"];
    songs.push("Ocean");
    show(songs.length);
23. 23.💾 What number does this code show?
    let notes = ["Maths", "Art", "Science", "Sports"];
    notes.push("Hindi");
    notes.push("Music");
    show(notes.length);
24. 24.💾 Where should the app save your last game level: on the phone or in the cloud? (a) in the cloud (b) on the phone
25. 25.💾 What does this code show? (Positions start at 0.)
    let friends = ["Riya", "Zoya", "Kabir"];
    show(friends[1]); (a) Riya (b) Kabir (c) Zoya
26. 26.True or false: chat messages to friends fits saving on the phone. (a) True (b) False
27. 27.💾 Which can hold many values in order? (a) a switch (b) a single number (c) a list (d) a button
28. 28.True or false: a shared to-do list fits saving in the cloud. (a) False (b) True
29. 29.💾 What number does this code show?
    let notes = ["Art", "Science", "Music", "Sports"];
    notes.push("Hindi");
    show(notes.length);
30. 30.💾 What does this code show? (Positions start at 0.)
    let songs = ["Rain", "Kites", "Stars", "Ocean"];
    show(songs[2]); (a) Stars (b) Rain (c) Ocean (d) Kites
31. 31.💾 pop() takes off the last item. What does this code show?
    let songs = ["Stars", "Monsoon", "Sunrise"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Stars (b) Monsoon (c) Sunrise
32. 32.Which of these fits saving in the cloud? (a) a class leaderboard (b) a draft you are typing (c) the sound on/off setting (d) notes to read offline
33. 33.True or false: your last game level fits saving in the cloud. (a) True (b) False
34. 34.💾 What does this code show? (Positions start at 0.)
    let friends = ["Meera", "Riya", "Aman"];
    show(friends[1]); (a) Meera (b) Riya (c) Aman
35. 35.💾 What number does this code show?
    let friends = ["Meera", "Arjun", "Zoya"];
    friends.push("Aman");
    friends.push("Kabir");
    show(friends.length);
36. 36.💾 What number does this code show?
    let lives = 9;
    lives = lives - 1;
    lives = lives + 2;
    show(lives);
37. 37.💾 pop() takes off the last item. What does this code show?
    let notes = ["Music", "Sports", "Hindi", "Art", "Science"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Music (b) Sports (c) Hindi (d) Art
38. 38.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) in the cloud (b) on the phone
39. 39.💾 What number does this code show?
    let notes = ["Maths", "Science"];
    notes.push("Hindi");
    show(notes.length);
40. 40.Which of these fits saving in the cloud? (a) the sound on/off setting (b) photos on two devices (c) a draft you are typing (d) notes to read offline

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