App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 397 · 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 songs = ["Rain", "Ocean", "Sunrise"];
   songs.push("Kites");
   songs.push("Stars");
   show(songs.length);
2. 2.💾 pop() takes off the last item. What does this code show?
   let notes = ["Sports", "Hindi", "Art"];
   notes.pop();
   show(notes[notes.length - 1]); (a) Hindi (b) Art (c) Sports
3. 3.💾 pop() takes off the last item. What does this code show?
   let friends = ["Meera", "Riya", "Aman", "Arjun"];
   friends.pop();
   show(friends[friends.length - 1]); (a) Meera (b) Arjun (c) Aman (d) Riya
4. 4.💾 Where should the app save notes to read offline: on the phone or in the cloud? (a) on the phone (b) in the cloud
5. 5.💾 pop() takes off the last item. What does this code show?
   let songs = ["Sunrise", "Rain", "Monsoon"];
   songs.pop();
   show(songs[songs.length - 1]); (a) Monsoon (b) Rain (c) Sunrise
6. 6.💾 What does this code show? (Positions start at 0.)
   let songs = ["Ocean", "Sunrise", "Stars", "Rain", "Kites"];
   show(songs[0]); (a) Sunrise (b) Stars (c) Ocean (d) Rain
7. 7.💾 What number does this code show?
   let score = 5;
   score = score - 2;
   score = score + 1;
   show(score);
8. 8.Which of these fits saving on the phone? (a) chat messages to friends (b) a class leaderboard (c) photos on two devices (d) the sound on/off setting
9. 9.Which of these fits saving on the phone? (a) photos on two devices (b) a class leaderboard (c) chat messages to friends (d) a draft you are typing
10. 10.💾 Which works with no internet at all? (a) a cloud leaderboard (b) a shared chat (c) a cloud backup (d) data saved on the phone
11. 11.💾 In most code, the first item of a list is at position ___. (a) 10 (b) 0 (c) 2 (d) 1
12. 12.Which of these fits saving on the phone? (a) your last game level (b) photos on two devices (c) a class leaderboard (d) chat messages to friends
13. 13.💾 Where should the app save a draft you are typing: on the phone or in the cloud? (a) on the phone (b) in the cloud
14. 14.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) on the phone (b) in the cloud
15. 15.True or false: your last game level fits saving in the cloud. (a) True (b) False
16. 16.💾 Where should the app save your last game level: on the phone or in the cloud? (a) on the phone (b) in the cloud
17. 17.💾 What number does this code show?
    let coins = 8;
    coins = coins - 3;
    coins = coins + 4;
    show(coins);
18. 18.💾 What does this code show? (Positions start at 0.)
    let songs = ["Rain", "Sunrise", "Stars", "Ocean", "Monsoon"];
    show(songs[1]); (a) Ocean (b) Rain (c) Sunrise (d) Stars
19. 19.💾 What number does this code show?
    let stars = 3;
    stars = stars - 2;
    stars = stars + 5;
    show(stars);
20. 20.💾 What is a variable? (a) a picture (b) a named box for a value (c) a type of screen (d) a phone setting
21. 21.💾 What number does this code show?
    let score = 3;
    score = score - 1;
    score = score + 2;
    show(score);
22. 22.💾 What number does this code show?
    let notes = ["Maths", "Science", "Art"];
    notes.push("Music");
    show(notes.length);
23. 23.True or false: chat messages to friends fits saving on the phone. (a) False (b) True
24. 24.💾 What does this code show? (Positions start at 0.)
    let songs = ["Monsoon", "Ocean", "Rain"];
    show(songs[0]); (a) Monsoon (b) Rain (c) Ocean
25. 25.💾 What number does this code show?
    let lives = 9;
    lives = lives - 7;
    lives = lives + 3;
    show(lives);
26. 26.💾 pop() takes off the last item. What does this code show?
    let friends = ["Meera", "Kabir", "Zoya", "Riya"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Kabir (b) Zoya (c) Riya (d) Meera
27. 27.💾 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
28. 28.True or false: photos on two devices fits saving on the phone. (a) False (b) True
29. 29.True or false: the sound on/off setting fits saving in the cloud. (a) True (b) False
30. 30.💾 Data saved only on the phone is lost when ___. (a) the screen turns off (b) the app is closed (c) you send a message (d) the phone is lost
31. 31.💾 What number does this code show?
    let points = 5;
    points = points - 1;
    points = points + 2;
    show(points);
32. 32.💾 What number does this code show?
    let notes = ["Science", "Maths", "Art", "Hindi"];
    notes.push("Music");
    notes.push("Sports");
    show(notes.length);
33. 33.True or false: a class leaderboard fits saving on the phone. (a) True (b) False
34. 34.💾 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) Kites (b) Stars (c) Rain (d) Sunrise
35. 35.True or false: a shared to-do list fits saving in the cloud. (a) False (b) True
36. 36.True or false: notes to read offline fits saving on the phone. (a) False (b) True
37. 37.💾 What number does this code show?
    let coins = 6;
    coins = coins - 6;
    coins = coins + 5;
    show(coins);
38. 38.Which of these fits saving in the cloud? (a) chat messages to friends (b) your last game level (c) notes to read offline (d) a draft you are typing
39. 39.True or false: a draft you are typing fits saving in the cloud. (a) True (b) False
40. 40.💾 What number does this code show?
    let lives = 5;
    lives = lives - 2;
    lives = lives + 4;
    show(lives);

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