App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 231 · 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.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) in the cloud (b) on the phone
2. 2.Which of these fits saving in the cloud? (a) photos on two devices (b) a draft you are typing (c) your last game level (d) notes to read offline
3. 3.💾 In most code, the first item of a list is at position ___. (a) 10 (b) 0 (c) 2 (d) 1
4. 4.💾 What number does this code show?
   let coins = 3;
   coins = coins - 1;
   coins = coins + 1;
   show(coins);
5. 5.Which of these fits saving on the phone? (a) a class leaderboard (b) your last game level (c) chat messages to friends (d) photos on two devices
6. 6.💾 What number does this code show?
   let songs = ["Ocean", "Sunrise"];
   songs.push("Kites");
   show(songs.length);
7. 7.💾 What is a variable? (a) a phone setting (b) a type of screen (c) a picture (d) a named box for a value
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.Which of these fits saving in the cloud? (a) the sound on/off setting (b) your last game level (c) a shared to-do list (d) a draft you are typing
10. 10.Which of these fits saving in the cloud? (a) the sound on/off setting (b) your last game level (c) chat messages to friends (d) notes to read offline
11. 11.💾 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
12. 12.💾 What number does this code show?
    let score = 8;
    score = score - 1;
    score = score + 5;
    show(score);
13. 13.True or false: your last game level fits saving on the phone. (a) True (b) False
14. 14.💾 Data saved only on the phone is lost when ___. (a) the phone is lost (b) you send a message (c) the app is closed (d) the screen turns off
15. 15.💾 pop() takes off the last item. What does this code show?
    let songs = ["Rain", "Stars", "Monsoon"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Stars (b) Monsoon (c) Rain
16. 16.💾 What number does this code show?
    let score = 6;
    score = score - 4;
    score = score + 4;
    show(score);
17. 17.💾 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
18. 18.💾 What does this code show? (Positions start at 0.)
    let songs = ["Monsoon", "Stars", "Rain", "Kites", "Sunrise"];
    show(songs[2]); (a) Stars (b) Rain (c) Kites (d) Monsoon
19. 19.💾 What does this code show? (Positions start at 0.)
    let notes = ["Sports", "Hindi", "Music", "Maths"];
    show(notes[0]); (a) Hindi (b) Music (c) Sports (d) Maths
20. 20.True or false: the sound on/off setting fits saving in the cloud. (a) False (b) True
21. 21.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) on the phone (b) in the cloud
22. 22.💾 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
23. 23.💾 pop() takes off the last item. What does this code show?
    let songs = ["Kites", "Stars", "Rain", "Monsoon", "Ocean"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Monsoon (b) Kites (c) Stars (d) Rain
24. 24.💾 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
25. 25.💾 What number does this code show?
    let songs = ["Monsoon", "Kites"];
    songs.push("Ocean");
    songs.push("Rain");
    show(songs.length);
26. 26.💾 What number does this code show?
    let points = 3;
    points = points - 3;
    points = points + 1;
    show(points);
27. 27.💾 What number does this code show?
    let points = 3;
    points = points - 1;
    points = points + 2;
    show(points);
28. 28.True or false: notes to read offline fits saving on the phone. (a) True (b) False
29. 29.💾 What number does this code show?
    let songs = ["Kites", "Sunrise"];
    songs.push("Rain");
    show(songs.length);
30. 30.💾 What number does this code show?
    let notes = ["Science", "Sports", "Art"];
    notes.push("Maths");
    notes.push("Music");
    show(notes.length);
31. 31.💾 Which can hold many values in order? (a) a list (b) a single number (c) a switch (d) a button
32. 32.True or false: photos on two devices fits saving in the cloud. (a) True (b) False
33. 33.💾 pop() takes off the last item. What does this code show?
    let notes = ["Hindi", "Maths", "Sports", "Science"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Sports (b) Science (c) Maths (d) Hindi
34. 34.💾 pop() takes off the last item. What does this code show?
    let friends = ["Aman", "Riya", "Arjun", "Zoya", "Kabir"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Arjun (b) Riya (c) Aman (d) Zoya
35. 35.💾 What does this code show? (Positions start at 0.)
    let notes = ["Hindi", "Music", "Science", "Sports"];
    show(notes[1]); (a) Sports (b) Music (c) Hindi (d) Science
36. 36.💾 pop() takes off the last item. What does this code show?
    let notes = ["Art", "Music", "Science", "Sports"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Sports (b) Art (c) Science (d) Music
37. 37.💾 pop() takes off the last item. What does this code show?
    let friends = ["Riya", "Kabir", "Zoya", "Meera"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Riya (b) Kabir (c) Meera (d) Zoya
38. 38.💾 Saving data in the cloud lets you ___. (a) never need a password (b) shrink the app (c) use it on any device (d) skip the internet
39. 39.💾 What number does this code show?
    let coins = 6;
    coins = coins - 6;
    coins = coins + 4;
    show(coins);
40. 40.True or false: your last game level fits saving in the cloud. (a) True (b) False

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