App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 487 · 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.True or false: a draft you are typing fits saving on the phone. (a) True (b) False
2. 2.💾 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
3. 3.💾 What number does this code show?
   let friends = ["Aman", "Arjun", "Meera"];
   friends.push("Zoya");
   friends.push("Riya");
   show(friends.length);
4. 4.💾 What number does this code show?
   let points = 7;
   points = points - 4;
   points = points + 1;
   show(points);
5. 5.True or false: chat messages to friends fits saving on the phone. (a) False (b) True
6. 6.💾 What number does this code show?
   let coins = 4;
   coins = coins - 3;
   coins = coins + 3;
   show(coins);
7. 7.💾 What number does this code show?
   let points = 4;
   points = points - 1;
   points = points + 5;
   show(points);
8. 8.💾 What number does this code show?
   let songs = ["Stars", "Ocean"];
   songs.push("Monsoon");
   songs.push("Rain");
   show(songs.length);
9. 9.💾 Where should the app save a shared to-do list: on the phone or in the cloud? (a) in the cloud (b) on the phone
10. 10.💾 Where should the app save notes to read offline: on the phone or in the cloud? (a) in the cloud (b) on the phone
11. 11.💾 In most code, the first item of a list is at position ___. (a) 1 (b) 10 (c) 0 (d) 2
12. 12.Which of these fits saving on the phone? (a) a shared to-do list (b) notes to read offline (c) chat messages to friends (d) photos on two devices
13. 13.💾 What does this code show? (Positions start at 0.)
    let friends = ["Zoya", "Meera", "Aman"];
    show(friends[2]); (a) Zoya (b) Aman (c) Meera
14. 14.💾 What number does this code show?
    let notes = ["Music", "Maths", "Art"];
    notes.push("Science");
    show(notes.length);
15. 15.True or false: a class leaderboard fits saving on the phone. (a) True (b) False
16. 16.💾 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
17. 17.True or false: your last game level fits saving on the phone. (a) False (b) True
18. 18.💾 Which can hold many values in order? (a) a switch (b) a list (c) a button (d) a single number
19. 19.💾 What does this code show? (Positions start at 0.)
    let notes = ["Music", "Sports", "Maths"];
    show(notes[1]); (a) Maths (b) Music (c) Sports
20. 20.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) on the phone (b) in the cloud
21. 21.Which of these fits saving in the cloud? (a) the sound on/off setting (b) a shared to-do list (c) notes to read offline (d) a draft you are typing
22. 22.Which of these fits saving in the cloud? (a) the sound on/off setting (b) a draft you are typing (c) photos on two devices (d) notes to read offline
23. 23.True or false: your last game level fits saving in the cloud. (a) False (b) True
24. 24.💾 Which works with no internet at all? (a) a cloud backup (b) a cloud leaderboard (c) data saved on the phone (d) a shared chat
25. 25.💾 pop() takes off the last item. What does this code show?
    let friends = ["Arjun", "Kabir", "Riya"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Kabir (b) Riya (c) Arjun
26. 26.💾 pop() takes off the last item. What does this code show?
    let friends = ["Kabir", "Arjun", "Riya"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Arjun (b) Riya (c) Kabir
27. 27.💾 What number does this code show?
    let stars = 4;
    stars = stars - 2;
    stars = stars + 5;
    show(stars);
28. 28.True or false: the sound on/off setting fits saving on the phone. (a) True (b) False
29. 29.💾 What number does this code show?
    let friends = ["Meera", "Zoya", "Kabir", "Arjun"];
    friends.push("Riya");
    friends.push("Aman");
    show(friends.length);
30. 30.💾 What number does this code show?
    let notes = ["Sports", "Maths", "Art", "Hindi"];
    notes.push("Science");
    show(notes.length);
31. 31.💾 What number does this code show?
    let coins = 4;
    coins = coins - 1;
    coins = coins + 4;
    show(coins);
32. 32.💾 What number does this code show?
    let notes = ["Science", "Sports", "Hindi", "Music"];
    notes.push("Maths");
    show(notes.length);
33. 33.💾 What number does this code show?
    let lives = 3;
    lives = lives - 2;
    lives = lives + 3;
    show(lives);
34. 34.💾 pop() takes off the last item. What does this code show?
    let notes = ["Art", "Music", "Sports"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Sports (b) Art (c) Music
35. 35.True or false: notes to read offline fits saving on the phone. (a) True (b) False
36. 36.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) on the phone (b) in the cloud
37. 37.💾 What number does this code show?
    let songs = ["Kites", "Sunrise"];
    songs.push("Ocean");
    songs.push("Rain");
    show(songs.length);
38. 38.💾 What number does this code show?
    let points = 5;
    points = points - 1;
    points = points + 2;
    show(points);
39. 39.💾 What number does this code show?
    let points = 4;
    points = points - 3;
    points = points + 1;
    show(points);
40. 40.💾 What number does this code show?
    let friends = ["Kabir", "Riya"];
    friends.push("Zoya");
    show(friends.length);

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