App Dev Worksheet: Variables, Lists and Saving

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

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