App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 216 · 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 is a variable? (a) a named box for a value (b) a type of screen (c) a phone setting (d) a picture
2. 2.💾 What number does this code show?
   let notes = ["Music", "Hindi"];
   notes.push("Science");
   show(notes.length);
3. 3.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) in the cloud (b) on the phone
4. 4.True or false: a draft you are typing fits saving on the phone. (a) True (b) False
5. 5.💾 Data saved only on the phone is lost when ___. (a) the app is closed (b) the phone is lost (c) the screen turns off (d) you send a message
6. 6.💾 Which works with no internet at all? (a) a cloud leaderboard (b) data saved on the phone (c) a shared chat (d) a cloud backup
7. 7.True or false: chat messages to friends fits saving in the cloud. (a) True (b) False
8. 8.💾 What number does this code show?
   let songs = ["Rain", "Kites", "Ocean"];
   songs.push("Monsoon");
   songs.push("Sunrise");
   show(songs.length);
9. 9.True or false: a class leaderboard fits saving on the phone. (a) False (b) True
10. 10.💾 What number does this code show?
    let songs = ["Sunrise", "Stars", "Rain", "Ocean"];
    songs.push("Monsoon");
    songs.push("Kites");
    show(songs.length);
11. 11.True or false: notes to read offline fits saving on the phone. (a) True (b) False
12. 12.💾 What does this code show? (Positions start at 0.)
    let notes = ["Music", "Maths", "Science", "Sports", "Hindi"];
    show(notes[4]); (a) Hindi (b) Science (c) Maths (d) Music
13. 13.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) on the phone (b) in the cloud
14. 14.💾 What does this code show? (Positions start at 0.)
    let songs = ["Kites", "Rain", "Sunrise", "Ocean"];
    show(songs[0]); (a) Sunrise (b) Kites (c) Rain (d) Ocean
15. 15.💾 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
16. 16.💾 pop() takes off the last item. What does this code show?
    let notes = ["Sports", "Maths", "Art", "Hindi"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Sports (b) Hindi (c) Maths (d) Art
17. 17.True or false: your last game level fits saving in the cloud. (a) True (b) False
18. 18.True or false: the sound on/off setting fits saving in the cloud. (a) True (b) False
19. 19.💾 In most code, the first item of a list is at position ___. (a) 1 (b) 10 (c) 2 (d) 0
20. 20.💾 What number does this code show?
    let stars = 8;
    stars = stars - 5;
    stars = stars + 4;
    show(stars);
21. 21.💾 Which can hold many values in order? (a) a single number (b) a switch (c) a button (d) a list
22. 22.💾 pop() takes off the last item. What does this code show?
    let notes = ["Art", "Maths", "Science"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Science (b) Art (c) Maths
23. 23.True or false: photos on two devices fits saving on the phone. (a) False (b) True
24. 24.True or false: the sound on/off setting fits saving on the phone. (a) True (b) False
25. 25.True or false: a shared to-do list fits saving on the phone. (a) False (b) True
26. 26.💾 What number does this code show?
    let stars = 6;
    stars = stars - 3;
    stars = stars + 1;
    show(stars);
27. 27.True or false: photos on two devices fits saving in the cloud. (a) True (b) False
28. 28.True or false: a draft you are typing fits saving in the cloud. (a) True (b) False
29. 29.💾 What number does this code show?
    let points = 7;
    points = points - 6;
    points = points + 3;
    show(points);
30. 30.💾 What does this code show? (Positions start at 0.)
    let notes = ["Art", "Music", "Science", "Hindi", "Maths"];
    show(notes[1]); (a) Art (b) Science (c) Hindi (d) Music
31. 31.💾 Where should the app save notes to read offline: on the phone or in the cloud? (a) on the phone (b) in the cloud
32. 32.True or false: chat messages to friends fits saving on the phone. (a) True (b) False
33. 33.💾 What does this code show? (Positions start at 0.)
    let friends = ["Aman", "Arjun", "Riya", "Meera", "Kabir"];
    show(friends[0]); (a) Aman (b) Meera (c) Riya (d) Arjun
34. 34.Which of these fits saving in the cloud? (a) the sound on/off setting (b) notes to read offline (c) a class leaderboard (d) a draft you are typing
35. 35.💾 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
36. 36.💾 What number does this code show?
    let friends = ["Arjun", "Meera", "Aman"];
    friends.push("Riya");
    friends.push("Kabir");
    show(friends.length);
37. 37.💾 What number does this code show?
    let notes = ["Music", "Art"];
    notes.push("Science");
    notes.push("Sports");
    show(notes.length);
38. 38.True or false: notes to read offline fits saving in the cloud. (a) True (b) False
39. 39.Which of these fits saving in the cloud? (a) chat messages to friends (b) the sound on/off setting (c) a draft you are typing (d) your last game level
40. 40.💾 What does this code show? (Positions start at 0.)
    let friends = ["Zoya", "Meera", "Aman"];
    show(friends[0]); (a) Meera (b) Aman (c) Zoya

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