App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 225 · 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 = ["Music", "Maths"];
   notes.push("Hindi");
   notes.push("Science");
   show(notes.length);
2. 2.Which of these fits saving in the cloud? (a) a shared to-do list (b) your last game level (c) notes to read offline (d) a draft you are typing
3. 3.Which of these fits saving on the phone? (a) photos on two devices (b) your last game level (c) a class leaderboard (d) chat messages to friends
4. 4.💾 In most code, the first item of a list is at position ___. (a) 2 (b) 1 (c) 0 (d) 10
5. 5.💾 What is a variable? (a) a type of screen (b) a picture (c) a phone setting (d) a named box for a value
6. 6.True or false: a draft you are typing fits saving on the phone. (a) True (b) False
7. 7.Which of these fits saving on the phone? (a) chat messages to friends (b) a shared to-do list (c) a draft you are typing (d) photos on two devices
8. 8.True or false: chat messages to friends fits saving on the phone. (a) False (b) True
9. 9.💾 What number does this code show?
   let points = 9;
   points = points - 6;
   points = points + 3;
   show(points);
10. 10.💾 Saving data in the cloud lets you ___. (a) use it on any device (b) shrink the app (c) never need a password (d) skip the internet
11. 11.💾 What number does this code show?
    let friends = ["Aman", "Zoya"];
    friends.push("Riya");
    show(friends.length);
12. 12.💾 What does this code show? (Positions start at 0.)
    let friends = ["Meera", "Kabir", "Riya"];
    show(friends[1]); (a) Kabir (b) Riya (c) Meera
13. 13.True or false: your last game level fits saving in the cloud. (a) True (b) False
14. 14.💾 pop() takes off the last item. What does this code show?
    let notes = ["Music", "Sports", "Art", "Maths"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Sports (b) Music (c) Art (d) Maths
15. 15.💾 Which can hold many values in order? (a) a button (b) a single number (c) a switch (d) a list
16. 16.True or false: notes to read offline fits saving in the cloud. (a) False (b) True
17. 17.💾 What number does this code show?
    let coins = 5;
    coins = coins - 2;
    coins = coins + 1;
    show(coins);
18. 18.💾 pop() takes off the last item. What does this code show?
    let friends = ["Riya", "Arjun", "Meera", "Kabir"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Kabir (b) Meera (c) Riya (d) Arjun
19. 19.True or false: a shared to-do list fits saving on the phone. (a) True (b) False
20. 20.💾 Which works with no internet at all? (a) a cloud backup (b) a cloud leaderboard (c) data saved on the phone (d) a shared chat
21. 21.💾 Where should the app save notes to read offline: on the phone or in the cloud? (a) on the phone (b) in the cloud
22. 22.💾 What number does this code show?
    let songs = ["Monsoon", "Ocean", "Kites"];
    songs.push("Rain");
    songs.push("Stars");
    show(songs.length);
23. 23.True or false: a draft you are typing fits saving in the cloud. (a) True (b) False
24. 24.💾 pop() takes off the last item. What does this code show?
    let songs = ["Rain", "Ocean", "Sunrise", "Kites"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Kites (b) Sunrise (c) Rain (d) Ocean
25. 25.💾 pop() takes off the last item. What does this code show?
    let notes = ["Music", "Art", "Maths"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Music (b) Maths (c) Art
26. 26.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) on the phone (b) in the cloud
27. 27.💾 Where should the app save the sound on/off setting: on the phone or in the cloud? (a) in the cloud (b) on the phone
28. 28.💾 pop() takes off the last item. What does this code show?
    let songs = ["Ocean", "Rain", "Sunrise", "Stars"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Ocean (b) Rain (c) Sunrise (d) Stars
29. 29.💾 What number does this code show?
    let friends = ["Kabir", "Riya", "Meera", "Aman"];
    friends.push("Arjun");
    show(friends.length);
30. 30.💾 What does this code show? (Positions start at 0.)
    let friends = ["Riya", "Meera", "Arjun", "Kabir", "Zoya"];
    show(friends[1]); (a) Riya (b) Arjun (c) Kabir (d) Meera
31. 31.Which of these fits saving on the phone? (a) a shared to-do list (b) photos on two devices (c) chat messages to friends (d) notes to read offline
32. 32.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) on the phone (b) in the cloud
33. 33.True or false: your last game level fits saving on the phone. (a) False (b) True
34. 34.True or false: the sound on/off setting fits saving in the cloud. (a) False (b) True
35. 35.💾 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
36. 36.💾 What number does this code show?
    let score = 6;
    score = score - 2;
    score = score + 2;
    show(score);
37. 37.Which of these fits saving in the cloud? (a) chat messages to friends (b) notes to read offline (c) the sound on/off setting (d) your last game level
38. 38.💾 pop() takes off the last item. What does this code show?
    let friends = ["Meera", "Arjun", "Zoya", "Aman"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Zoya (b) Arjun (c) Meera (d) Aman
39. 39.💾 What number does this code show?
    let friends = ["Kabir", "Zoya"];
    friends.push("Meera");
    friends.push("Arjun");
    show(friends.length);
40. 40.💾 Data saved only on the phone is lost when ___. (a) the phone is lost (b) you send a message (c) the screen turns off (d) the app is closed

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