App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 642 · 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 = ["Art", "Hindi", "Maths"];
   notes.push("Science");
   show(notes.length);
2. 2.True or false: photos on two devices fits saving on the phone. (a) False (b) True
3. 3.💾 pop() takes off the last item. What does this code show?
   let notes = ["Hindi", "Sports", "Maths"];
   notes.pop();
   show(notes[notes.length - 1]); (a) Sports (b) Hindi (c) Maths
4. 4.💾 Where should the app save photos on two devices: on the phone or in the cloud? (a) on the phone (b) in the cloud
5. 5.💾 In most code, the first item of a list is at position ___. (a) 10 (b) 1 (c) 2 (d) 0
6. 6.Which of these fits saving in the cloud? (a) a class leaderboard (b) the sound on/off setting (c) your last game level (d) notes to read offline
7. 7.💾 What number does this code show?
   let score = 8;
   score = score - 6;
   score = score + 2;
   show(score);
8. 8.💾 What number does this code show?
   let coins = 8;
   coins = coins - 7;
   coins = coins + 2;
   show(coins);
9. 9.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) in the cloud (b) on the phone
10. 10.💾 Data saved only on the phone is lost when ___. (a) you send a message (b) the phone is lost (c) the screen turns off (d) the app is closed
11. 11.💾 Saving data in the cloud lets you ___. (a) shrink the app (b) use it on any device (c) never need a password (d) skip the internet
12. 12.💾 What number does this code show?
    let notes = ["Music", "Hindi", "Art"];
    notes.push("Science");
    notes.push("Sports");
    show(notes.length);
13. 13.💾 What number does this code show?
    let stars = 9;
    stars = stars - 1;
    stars = stars + 1;
    show(stars);
14. 14.💾 What number does this code show?
    let songs = ["Ocean", "Rain"];
    songs.push("Sunrise");
    show(songs.length);
15. 15.💾 pop() takes off the last item. What does this code show?
    let friends = ["Zoya", "Kabir", "Riya"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Riya (b) Zoya (c) Kabir
16. 16.💾 What number does this code show?
    let friends = ["Kabir", "Meera", "Riya"];
    friends.push("Aman");
    friends.push("Zoya");
    show(friends.length);
17. 17.True or false: a draft you are typing fits saving on the phone. (a) False (b) True
18. 18.💾 What does this code show? (Positions start at 0.)
    let notes = ["Hindi", "Sports", "Art", "Maths"];
    show(notes[3]); (a) Maths (b) Hindi (c) Art (d) Sports
19. 19.💾 What number does this code show?
    let lives = 7;
    lives = lives - 2;
    lives = lives + 5;
    show(lives);
20. 20.💾 What is a variable? (a) a picture (b) a type of screen (c) a phone setting (d) a named box for a value
21. 21.💾 Where should the app save notes to read offline: on the phone or in the cloud? (a) in the cloud (b) on the phone
22. 22.💾 Which works with no internet at all? (a) data saved on the phone (b) a shared chat (c) a cloud backup (d) a cloud leaderboard
23. 23.Which of these fits saving on the phone? (a) chat messages to friends (b) notes to read offline (c) a shared to-do list (d) a class leaderboard
24. 24.Which of these fits saving in the cloud? (a) notes to read offline (b) a shared to-do list (c) the sound on/off setting (d) a draft you are typing
25. 25.💾 pop() takes off the last item. What does this code show?
    let songs = ["Stars", "Monsoon", "Sunrise", "Rain", "Ocean"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Rain (b) Stars (c) Sunrise (d) Monsoon
26. 26.Which of these fits saving in the cloud? (a) notes to read offline (b) the sound on/off setting (c) your last game level (d) photos on two devices
27. 27.True or false: the sound on/off setting fits saving on the phone. (a) False (b) True
28. 28.💾 What number does this code show?
    let score = 5;
    score = score - 3;
    score = score + 3;
    show(score);
29. 29.True or false: a class leaderboard fits saving on the phone. (a) True (b) False
30. 30.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) in the cloud (b) on the phone
31. 31.💾 Which can hold many values in order? (a) a button (b) a list (c) a single number (d) a switch
32. 32.💾 What does this code show? (Positions start at 0.)
    let friends = ["Arjun", "Aman", "Kabir", "Meera"];
    show(friends[1]); (a) Meera (b) Arjun (c) Aman (d) Kabir
33. 33.Which of these fits saving on the phone? (a) a class leaderboard (b) photos on two devices (c) chat messages to friends (d) a draft you are typing
34. 34.💾 pop() takes off the last item. What does this code show?
    let friends = ["Zoya", "Kabir", "Meera", "Riya"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Riya (b) Meera (c) Zoya (d) Kabir
35. 35.💾 What number does this code show?
    let songs = ["Sunrise", "Rain", "Ocean"];
    songs.push("Monsoon");
    show(songs.length);
36. 36.💾 pop() takes off the last item. What does this code show?
    let friends = ["Riya", "Aman", "Zoya"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Aman (b) Zoya (c) Riya
37. 37.True or false: photos on two devices fits saving in the cloud. (a) True (b) False
38. 38.💾 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
39. 39.💾 What number does this code show?
    let songs = ["Rain", "Stars", "Kites", "Sunrise"];
    songs.push("Ocean");
    songs.push("Monsoon");
    show(songs.length);
40. 40.Which of these fits saving on the phone? (a) chat messages to friends (b) a shared to-do list (c) a class leaderboard (d) the sound on/off setting

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