App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 412 · 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 score = 7;
   score = score - 2;
   score = score + 2;
   show(score);
2. 2.💾 What number does this code show?
   let notes = ["Music", "Science"];
   notes.push("Maths");
   show(notes.length);
3. 3.💾 What number does this code show?
   let score = 3;
   score = score - 3;
   score = score + 1;
   show(score);
4. 4.💾 Data saved only on the phone is lost when ___. (a) the screen turns off (b) the phone is lost (c) the app is closed (d) you send a message
5. 5.💾 What is a variable? (a) a named box for a value (b) a picture (c) a type of screen (d) a phone setting
6. 6.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) on the phone (b) in the cloud
7. 7.💾 pop() takes off the last item. What does this code show?
   let friends = ["Kabir", "Zoya", "Meera", "Aman"];
   friends.pop();
   show(friends[friends.length - 1]); (a) Meera (b) Zoya (c) Kabir (d) Aman
8. 8.💾 Where should the app save photos on two devices: on the phone or in the cloud? (a) on the phone (b) in the cloud
9. 9.💾 Where should the app save notes to read offline: on the phone or in the cloud? (a) in the cloud (b) on the phone
10. 10.💾 Where should the app save your last game level: on the phone or in the cloud? (a) on the phone (b) in the cloud
11. 11.💾 What number does this code show?
    let points = 9;
    points = points - 1;
    points = points + 2;
    show(points);
12. 12.Which of these fits saving on the phone? (a) a shared to-do list (b) photos on two devices (c) notes to read offline (d) chat messages to friends
13. 13.True or false: chat messages to friends fits saving in the cloud. (a) True (b) False
14. 14.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) on the phone (b) in the cloud
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.💾 Which works with no internet at all? (a) a cloud leaderboard (b) data saved on the phone (c) a cloud backup (d) a shared chat
17. 17.Which of these fits saving on the phone? (a) the sound on/off setting (b) a shared to-do list (c) photos on two devices (d) chat messages to friends
18. 18.💾 What number does this code show?
    let points = 7;
    points = points - 4;
    points = points + 1;
    show(points);
19. 19.💾 Where should the app save a draft you are typing: on the phone or in the cloud? (a) on the phone (b) in the cloud
20. 20.Which of these fits saving on the phone? (a) a draft you are typing (b) a shared to-do list (c) photos on two devices (d) a class leaderboard
21. 21.💾 What number does this code show?
    let songs = ["Kites", "Monsoon"];
    songs.push("Stars");
    songs.push("Rain");
    show(songs.length);
22. 22.True or false: photos on two devices fits saving on the phone. (a) False (b) True
23. 23.True or false: notes to read offline fits saving in the cloud. (a) False (b) True
24. 24.💾 What number does this code show?
    let songs = ["Stars", "Rain", "Kites"];
    songs.push("Ocean");
    songs.push("Sunrise");
    show(songs.length);
25. 25.💾 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
26. 26.💾 What number does this code show?
    let notes = ["Music", "Maths"];
    notes.push("Sports");
    show(notes.length);
27. 27.True or false: a draft you are typing fits saving in the cloud. (a) True (b) False
28. 28.💾 What does this code show? (Positions start at 0.)
    let songs = ["Monsoon", "Ocean", "Stars", "Kites"];
    show(songs[0]); (a) Stars (b) Monsoon (c) Kites (d) Ocean
29. 29.💾 What number does this code show?
    let songs = ["Rain", "Sunrise", "Kites", "Ocean"];
    songs.push("Stars");
    songs.push("Monsoon");
    show(songs.length);
30. 30.True or false: a class leaderboard fits saving in the cloud. (a) True (b) False
31. 31.💾 What number does this code show?
    let points = 5;
    points = points - 1;
    points = points + 3;
    show(points);
32. 32.💾 Which can hold many values in order? (a) a single number (b) a button (c) a list (d) a switch
33. 33.True or false: photos on two devices fits saving in the cloud. (a) True (b) False
34. 34.💾 What number does this code show?
    let stars = 4;
    stars = stars - 3;
    stars = stars + 3;
    show(stars);
35. 35.💾 What number does this code show?
    let notes = ["Music", "Art", "Hindi"];
    notes.push("Maths");
    notes.push("Science");
    show(notes.length);
36. 36.💾 Saving data in the cloud lets you ___. (a) skip the internet (b) shrink the app (c) never need a password (d) use it on any device
37. 37.💾 pop() takes off the last item. What does this code show?
    let friends = ["Riya", "Meera", "Aman", "Zoya", "Kabir"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Riya (b) Aman (c) Zoya (d) Meera
38. 38.💾 pop() takes off the last item. What does this code show?
    let songs = ["Monsoon", "Ocean", "Stars", "Rain"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Ocean (b) Rain (c) Stars (d) Monsoon
39. 39.True or false: the sound on/off setting fits saving in the cloud. (a) False (b) True
40. 40.💾 In most code, the first item of a list is at position ___. (a) 1 (b) 0 (c) 10 (d) 2

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