App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 734 · 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", "Sports", "Hindi", "Science"];
   notes.push("Art");
   notes.push("Maths");
   show(notes.length);
2. 2.💾 What number does this code show?
   let stars = 4;
   stars = stars - 2;
   stars = stars + 4;
   show(stars);
3. 3.💾 What number does this code show?
   let points = 8;
   points = points - 5;
   points = points + 4;
   show(points);
4. 4.💾 pop() takes off the last item. What does this code show?
   let songs = ["Stars", "Kites", "Rain"];
   songs.pop();
   show(songs[songs.length - 1]); (a) Stars (b) Kites (c) Rain
5. 5.💾 What is a variable? (a) a picture (b) a named box for a value (c) a type of screen (d) a phone setting
6. 6.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) in the cloud (b) on the phone
7. 7.True or false: notes to read offline fits saving on the phone. (a) True (b) False
8. 8.True or false: a class leaderboard fits saving in the cloud. (a) False (b) True
9. 9.💾 pop() takes off the last item. What does this code show?
   let notes = ["Hindi", "Art", "Sports"];
   notes.pop();
   show(notes[notes.length - 1]); (a) Sports (b) Hindi (c) Art
10. 10.True or false: notes to read offline fits saving in the cloud. (a) True (b) False
11. 11.Which of these fits saving in the cloud? (a) your last game level (b) notes to read offline (c) chat messages to friends (d) a draft you are typing
12. 12.💾 What number does this code show?
    let points = 6;
    points = points - 1;
    points = points + 1;
    show(points);
13. 13.💾 Which works with no internet at all? (a) a cloud backup (b) data saved on the phone (c) a shared chat (d) a cloud leaderboard
14. 14.💾 Where should the app save notes to read offline: on the phone or in the cloud? (a) in the cloud (b) on the phone
15. 15.Which of these fits saving in the cloud? (a) a class leaderboard (b) a draft you are typing (c) the sound on/off setting (d) your last game level
16. 16.Which of these fits saving on the phone? (a) chat messages to friends (b) photos on two devices (c) the sound on/off setting (d) a shared to-do list
17. 17.💾 What number does this code show?
    let friends = ["Meera", "Kabir"];
    friends.push("Aman");
    show(friends.length);
18. 18.💾 In most code, the first item of a list is at position ___. (a) 10 (b) 0 (c) 2 (d) 1
19. 19.💾 pop() takes off the last item. What does this code show?
    let songs = ["Sunrise", "Monsoon", "Kites", "Stars", "Rain"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Kites (b) Sunrise (c) Stars (d) Monsoon
20. 20.💾 What number does this code show?
    let notes = ["Science", "Art"];
    notes.push("Hindi");
    show(notes.length);
21. 21.💾 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
22. 22.True or false: the sound on/off setting fits saving in the cloud. (a) False (b) True
23. 23.💾 What does this code show? (Positions start at 0.)
    let friends = ["Meera", "Aman", "Arjun"];
    show(friends[1]); (a) Aman (b) Meera (c) Arjun
24. 24.💾 pop() takes off the last item. What does this code show?
    let notes = ["Sports", "Music", "Maths", "Science", "Art"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Science (b) Music (c) Sports (d) Maths
25. 25.💾 What number does this code show?
    let notes = ["Art", "Music", "Maths", "Science"];
    notes.push("Sports");
    show(notes.length);
26. 26.💾 Where should the app save chat messages to friends: 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 notes = ["Sports", "Science", "Music", "Maths", "Art"];
    show(notes[0]); (a) Music (b) Maths (c) Science (d) Sports
28. 28.💾 What does this code show? (Positions start at 0.)
    let notes = ["Hindi", "Maths", "Music", "Art"];
    show(notes[0]); (a) Art (b) Maths (c) Hindi (d) Music
29. 29.Which of these fits saving on the phone? (a) chat messages to friends (b) a class leaderboard (c) notes to read offline (d) photos on two devices
30. 30.💾 What number does this code show?
    let notes = ["Maths", "Hindi", "Art"];
    notes.push("Science");
    notes.push("Music");
    show(notes.length);
31. 31.💾 What number does this code show?
    let notes = ["Science", "Music", "Maths", "Sports"];
    notes.push("Art");
    show(notes.length);
32. 32.💾 What number does this code show?
    let friends = ["Aman", "Arjun"];
    friends.push("Meera");
    friends.push("Riya");
    show(friends.length);
33. 33.Which of these fits saving on the phone? (a) your last game level (b) a shared to-do list (c) chat messages to friends (d) a class leaderboard
34. 34.💾 What number does this code show?
    let lives = 4;
    lives = lives - 2;
    lives = lives + 1;
    show(lives);
35. 35.💾 Where should the app save photos on two devices: on the phone or in the cloud? (a) on the phone (b) in the cloud
36. 36.💾 What number does this code show?
    let songs = ["Kites", "Stars", "Rain", "Sunrise"];
    songs.push("Monsoon");
    songs.push("Ocean");
    show(songs.length);
37. 37.💾 Where should the app save a shared to-do list: on the phone or in the cloud? (a) on the phone (b) in the cloud
38. 38.💾 What number does this code show?
    let songs = ["Kites", "Ocean"];
    songs.push("Sunrise");
    show(songs.length);
39. 39.💾 What number does this code show?
    let score = 4;
    score = score - 4;
    score = score + 4;
    show(score);
40. 40.💾 What number does this code show?
    let stars = 9;
    stars = stars - 4;
    stars = stars + 5;
    show(stars);

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