App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 456 · 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 friends = ["Arjun", "Aman"];
   friends.push("Meera");
   friends.push("Kabir");
   show(friends.length);
2. 2.Which of these fits saving on the phone? (a) chat messages to friends (b) your last game level (c) a shared to-do list (d) a class leaderboard
3. 3.💾 What number does this code show?
   let notes = ["Sports", "Maths"];
   notes.push("Art");
   notes.push("Science");
   show(notes.length);
4. 4.Which of these fits saving on the phone? (a) a shared to-do list (b) a class leaderboard (c) notes to read offline (d) chat messages to friends
5. 5.💾 Where should the app save your last game level: on the phone or in the cloud? (a) in the cloud (b) on the phone
6. 6.Which of these fits saving in the cloud? (a) notes to read offline (b) a draft you are typing (c) your last game level (d) chat messages to friends
7. 7.💾 What number does this code show?
   let friends = ["Aman", "Arjun"];
   friends.push("Meera");
   show(friends.length);
8. 8.💾 In most code, the first item of a list is at position ___. (a) 10 (b) 2 (c) 1 (d) 0
9. 9.True or false: photos on two devices fits saving in the cloud. (a) False (b) True
10. 10.Which of these fits saving in the cloud? (a) a draft you are typing (b) notes to read offline (c) photos on two devices (d) your last game level
11. 11.💾 Where should the app save photos on two devices: on the phone or in the cloud? (a) in the cloud (b) on the phone
12. 12.💾 What number does this code show?
    let songs = ["Sunrise", "Kites", "Monsoon"];
    songs.push("Ocean");
    songs.push("Stars");
    show(songs.length);
13. 13.💾 Where should the app save notes to read offline: on the phone or in the cloud? (a) on the phone (b) in the cloud
14. 14.💾 What number does this code show?
    let score = 3;
    score = score - 2;
    score = score + 1;
    show(score);
15. 15.💾 What number does this code show?
    let friends = ["Aman", "Meera", "Kabir"];
    friends.push("Zoya");
    show(friends.length);
16. 16.💾 What does this code show? (Positions start at 0.)
    let friends = ["Aman", "Riya", "Zoya", "Meera"];
    show(friends[0]); (a) Riya (b) Zoya (c) Aman (d) Meera
17. 17.💾 pop() takes off the last item. What does this code show?
    let songs = ["Rain", "Sunrise", "Kites", "Stars", "Ocean"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Stars (b) Kites (c) Sunrise (d) Rain
18. 18.💾 What does this code show? (Positions start at 0.)
    let songs = ["Sunrise", "Rain", "Kites"];
    show(songs[1]); (a) Sunrise (b) Kites (c) Rain
19. 19.True or false: notes to read offline fits saving on the phone. (a) True (b) False
20. 20.💾 Data saved only on the phone is lost when ___. (a) the screen turns off (b) the app is closed (c) the phone is lost (d) you send a message
21. 21.💾 What number does this code show?
    let notes = ["Art", "Sports", "Music", "Maths"];
    notes.push("Hindi");
    show(notes.length);
22. 22.💾 pop() takes off the last item. What does this code show?
    let songs = ["Rain", "Monsoon", "Sunrise", "Ocean"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Rain (b) Monsoon (c) Ocean (d) Sunrise
23. 23.True or false: your last game level fits saving in the cloud. (a) True (b) False
24. 24.💾 Which can hold many values in order? (a) a button (b) a list (c) a single number (d) a switch
25. 25.💾 What does this code show? (Positions start at 0.)
    let songs = ["Sunrise", "Rain", "Kites"];
    show(songs[0]); (a) Kites (b) Rain (c) Sunrise
26. 26.💾 pop() takes off the last item. What does this code show?
    let songs = ["Rain", "Stars", "Monsoon"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Rain (b) Stars (c) Monsoon
27. 27.True or false: a draft you are typing fits saving on the phone. (a) False (b) True
28. 28.💾 What is a variable? (a) a phone setting (b) a picture (c) a named box for a value (d) a type of screen
29. 29.💾 pop() takes off the last item. What does this code show?
    let songs = ["Stars", "Sunrise", "Kites"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Kites (b) Stars (c) Sunrise
30. 30.💾 pop() takes off the last item. What does this code show?
    let notes = ["Science", "Music", "Sports", "Maths"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Music (b) Science (c) Maths (d) Sports
31. 31.💾 pop() takes off the last item. What does this code show?
    let songs = ["Kites", "Ocean", "Sunrise", "Stars"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Sunrise (b) Kites (c) Ocean (d) Stars
32. 32.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) on the phone (b) in the cloud
33. 33.💾 pop() takes off the last item. What does this code show?
    let friends = ["Aman", "Kabir", "Zoya", "Riya"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Aman (b) Riya (c) Kabir (d) Zoya
34. 34.True or false: photos on two devices fits saving on the phone. (a) False (b) True
35. 35.💾 Which works with no internet at all? (a) a shared chat (b) a cloud leaderboard (c) a cloud backup (d) data saved on the phone
36. 36.True or false: a draft you are typing fits saving in the cloud. (a) False (b) True
37. 37.Which of these fits saving in the cloud? (a) a draft you are typing (b) a shared to-do list (c) your last game level (d) the sound on/off setting
38. 38.💾 What number does this code show?
    let score = 9;
    score = score - 9;
    score = score + 3;
    show(score);
39. 39.💾 pop() takes off the last item. What does this code show?
    let notes = ["Art", "Maths", "Sports"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Maths (b) Sports (c) Art
40. 40.True or false: notes to read offline fits saving in the cloud. (a) True (b) False

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