App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 270 · 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 notes = ["Sports", "Maths", "Art"];
   notes.push("Music");
   notes.push("Science");
   show(notes.length);
2. 2.💾 What number does this code show?
   let songs = ["Sunrise", "Kites", "Stars", "Monsoon"];
   songs.push("Rain");
   show(songs.length);
3. 3.💾 In most code, the first item of a list is at position ___. (a) 0 (b) 1 (c) 2 (d) 10
4. 4.Which of these fits saving on the phone? (a) photos on two devices (b) chat messages to friends (c) a class leaderboard (d) a draft you are typing
5. 5.💾 What number does this code show?
   let coins = 5;
   coins = coins - 1;
   coins = coins + 3;
   show(coins);
6. 6.💾 pop() takes off the last item. What does this code show?
   let notes = ["Science", "Art", "Music"];
   notes.pop();
   show(notes[notes.length - 1]); (a) Music (b) Art (c) Science
7. 7.💾 Saving data in the cloud lets you ___. (a) shrink the app (b) skip the internet (c) use it on any device (d) never need a password
8. 8.💾 What does this code show? (Positions start at 0.)
   let songs = ["Monsoon", "Stars", "Ocean", "Kites", "Rain"];
   show(songs[2]); (a) Ocean (b) Monsoon (c) Stars (d) Kites
9. 9.True or false: notes to read offline fits saving in the cloud. (a) False (b) True
10. 10.True or false: notes to read offline fits saving on the phone. (a) False (b) True
11. 11.💾 What is a variable? (a) a type of screen (b) a picture (c) a named box for a value (d) a phone setting
12. 12.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) on the phone (b) in the cloud
13. 13.True or false: your last game level fits saving on the phone. (a) False (b) True
14. 14.Which of these fits saving on the phone? (a) photos on two devices (b) a class leaderboard (c) a shared to-do list (d) notes to read offline
15. 15.True or false: photos on two devices fits saving in the cloud. (a) True (b) False
16. 16.Which of these fits saving in the cloud? (a) a draft you are typing (b) your last game level (c) notes to read offline (d) a class leaderboard
17. 17.💾 Which can hold many values in order? (a) a single number (b) a list (c) a button (d) a switch
18. 18.💾 Where should the app save photos on two devices: on the phone or in the cloud? (a) on the phone (b) in the cloud
19. 19.💾 What number does this code show?
    let coins = 4;
    coins = coins - 3;
    coins = coins + 5;
    show(coins);
20. 20.💾 What does this code show? (Positions start at 0.)
    let songs = ["Rain", "Stars", "Ocean", "Monsoon", "Kites"];
    show(songs[3]); (a) Stars (b) Ocean (c) Monsoon (d) Rain
21. 21.💾 What number does this code show?
    let notes = ["Hindi", "Sports"];
    notes.push("Music");
    show(notes.length);
22. 22.💾 What number does this code show?
    let points = 7;
    points = points - 3;
    points = points + 3;
    show(points);
23. 23.💾 What number does this code show?
    let friends = ["Zoya", "Aman", "Kabir"];
    friends.push("Riya");
    show(friends.length);
24. 24.💾 What number does this code show?
    let friends = ["Zoya", "Meera", "Riya"];
    friends.push("Aman");
    show(friends.length);
25. 25.💾 What number does this code show?
    let friends = ["Kabir", "Aman"];
    friends.push("Meera");
    friends.push("Zoya");
    show(friends.length);
26. 26.💾 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
27. 27.💾 What does this code show? (Positions start at 0.)
    let songs = ["Sunrise", "Monsoon", "Stars"];
    show(songs[1]); (a) Monsoon (b) Sunrise (c) Stars
28. 28.💾 What does this code show? (Positions start at 0.)
    let friends = ["Kabir", "Riya", "Zoya", "Aman"];
    show(friends[1]); (a) Zoya (b) Aman (c) Kabir (d) Riya
29. 29.Which of these fits saving on the phone? (a) a class leaderboard (b) the sound on/off setting (c) chat messages to friends (d) a shared to-do list
30. 30.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) in the cloud (b) on the phone
31. 31.💾 pop() takes off the last item. What does this code show?
    let songs = ["Rain", "Sunrise", "Monsoon", "Kites", "Stars"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Sunrise (b) Monsoon (c) Kites (d) Rain
32. 32.💾 What number does this code show?
    let notes = ["Music", "Maths"];
    notes.push("Science");
    show(notes.length);
33. 33.💾 What does this code show? (Positions start at 0.)
    let songs = ["Rain", "Kites", "Sunrise"];
    show(songs[1]); (a) Sunrise (b) Kites (c) Rain
34. 34.Which of these fits saving in the cloud? (a) photos on two devices (b) a draft you are typing (c) notes to read offline (d) the sound on/off setting
35. 35.💾 pop() takes off the last item. What does this code show?
    let songs = ["Sunrise", "Kites", "Ocean"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Ocean (b) Kites (c) Sunrise
36. 36.💾 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
37. 37.True or false: photos on two devices fits saving on the phone. (a) True (b) False
38. 38.💾 What number does this code show?
    let notes = ["Maths", "Music"];
    notes.push("Science");
    show(notes.length);
39. 39.💾 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
40. 40.💾 Where should the app save your last game level: on the phone or in the cloud? (a) in the cloud (b) on the phone

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