App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 371 · 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 coins = 4;
   coins = coins - 4;
   coins = coins + 2;
   show(coins);
2. 2.💾 What number does this code show?
   let friends = ["Aman", "Kabir"];
   friends.push("Zoya");
   show(friends.length);
3. 3.💾 What number does this code show?
   let stars = 7;
   stars = stars - 5;
   stars = stars + 4;
   show(stars);
4. 4.💾 What number does this code show?
   let score = 7;
   score = score - 3;
   score = score + 4;
   show(score);
5. 5.💾 What number does this code show?
   let songs = ["Kites", "Monsoon"];
   songs.push("Ocean");
   show(songs.length);
6. 6.💾 Where should the app save notes to read offline: on the phone or in the cloud? (a) on the phone (b) in the cloud
7. 7.💾 What number does this code show?
   let friends = ["Aman", "Arjun"];
   friends.push("Kabir");
   show(friends.length);
8. 8.💾 pop() takes off the last item. What does this code show?
   let friends = ["Aman", "Kabir", "Zoya"];
   friends.pop();
   show(friends[friends.length - 1]); (a) Kabir (b) Zoya (c) Aman
9. 9.💾 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
10. 10.💾 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
11. 11.True or false: notes to read offline fits saving on the phone. (a) False (b) True
12. 12.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) on the phone (b) in the cloud
13. 13.Which of these fits saving on the phone? (a) a draft you are typing (b) a class leaderboard (c) chat messages to friends (d) a shared to-do list
14. 14.💾 What number does this code show?
    let lives = 9;
    lives = lives - 5;
    lives = lives + 1;
    show(lives);
15. 15.💾 What does this code show? (Positions start at 0.)
    let notes = ["Music", "Hindi", "Sports", "Maths", "Art"];
    show(notes[3]); (a) Maths (b) Hindi (c) Music (d) Sports
16. 16.💾 What does this code show? (Positions start at 0.)
    let friends = ["Riya", "Kabir", "Meera", "Aman", "Zoya"];
    show(friends[3]); (a) Aman (b) Meera (c) Riya (d) Kabir
17. 17.💾 What number does this code show?
    let points = 6;
    points = points - 3;
    points = points + 2;
    show(points);
18. 18.💾 Where should the app save your last game level: on the phone or in the cloud? (a) on the phone (b) in the cloud
19. 19.💾 What number does this code show?
    let coins = 8;
    coins = coins - 7;
    coins = coins + 3;
    show(coins);
20. 20.💾 In most code, the first item of a list is at position ___. (a) 1 (b) 10 (c) 0 (d) 2
21. 21.💾 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
22. 22.💾 What number does this code show?
    let score = 3;
    score = score - 3;
    score = score + 1;
    show(score);
23. 23.💾 What number does this code show?
    let songs = ["Kites", "Ocean", "Sunrise"];
    songs.push("Rain");
    show(songs.length);
24. 24.Which of these fits saving in the cloud? (a) your last game level (b) a shared to-do list (c) notes to read offline (d) a draft you are typing
25. 25.💾 What number does this code show?
    let notes = ["Music", "Maths", "Sports", "Art"];
    notes.push("Science");
    show(notes.length);
26. 26.💾 What number does this code show?
    let notes = ["Hindi", "Maths", "Science"];
    notes.push("Music");
    notes.push("Sports");
    show(notes.length);
27. 27.💾 pop() takes off the last item. What does this code show?
    let songs = ["Sunrise", "Rain", "Stars"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Rain (b) Stars (c) Sunrise
28. 28.True or false: your last game level fits saving on the phone. (a) True (b) False
29. 29.💾 What number does this code show?
    let friends = ["Riya", "Meera", "Aman"];
    friends.push("Arjun");
    show(friends.length);
30. 30.💾 What does this code show? (Positions start at 0.)
    let friends = ["Aman", "Kabir", "Zoya"];
    show(friends[2]); (a) Zoya (b) Kabir (c) Aman
31. 31.True or false: chat messages to friends fits saving on the phone. (a) False (b) True
32. 32.Which of these fits saving in the cloud? (a) notes to read offline (b) a draft you are typing (c) photos on two devices (d) your last game level
33. 33.Which of these fits saving on the phone? (a) photos on two devices (b) the sound on/off setting (c) a shared to-do list (d) a class leaderboard
34. 34.💾 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
35. 35.💾 What number does this code show?
    let points = 4;
    points = points - 4;
    points = points + 1;
    show(points);
36. 36.💾 pop() takes off the last item. What does this code show?
    let notes = ["Art", "Maths", "Science"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Art (b) Maths (c) Science
37. 37.💾 Where should the app save photos on two devices: on the phone or in the cloud? (a) on the phone (b) in the cloud
38. 38.💾 pop() takes off the last item. What does this code show?
    let notes = ["Maths", "Science", "Art", "Music"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Music (b) Maths (c) Science (d) Art
39. 39.💾 Data saved only on the phone is lost when ___. (a) the screen turns off (b) the phone is lost (c) you send a message (d) the app is closed
40. 40.💾 What number does this code show?
    let friends = ["Riya", "Kabir"];
    friends.push("Zoya");
    show(friends.length);

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