App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 212 · 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 points = 9;
   points = points - 2;
   points = points + 5;
   show(points);
2. 2.💾 pop() takes off the last item. What does this code show?
   let songs = ["Monsoon", "Stars", "Ocean", "Rain"];
   songs.pop();
   show(songs[songs.length - 1]); (a) Stars (b) Ocean (c) Monsoon (d) Rain
3. 3.💾 What number does this code show?
   let songs = ["Sunrise", "Stars", "Ocean"];
   songs.push("Monsoon");
   songs.push("Kites");
   show(songs.length);
4. 4.💾 What number does this code show?
   let score = 7;
   score = score - 3;
   score = score + 2;
   show(score);
5. 5.True or false: a class leaderboard fits saving in the cloud. (a) False (b) True
6. 6.💾 What does this code show? (Positions start at 0.)
   let friends = ["Zoya", "Riya", "Meera"];
   show(friends[2]); (a) Riya (b) Meera (c) Zoya
7. 7.💾 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
8. 8.True or false: the sound on/off setting fits saving in the cloud. (a) True (b) False
9. 9.Which of these fits saving in the cloud? (a) your last game level (b) notes to read offline (c) a shared to-do list (d) the sound on/off setting
10. 10.💾 What number does this code show?
    let coins = 8;
    coins = coins - 7;
    coins = coins + 4;
    show(coins);
11. 11.💾 In most code, the first item of a list is at position ___. (a) 10 (b) 2 (c) 0 (d) 1
12. 12.💾 Data saved only on the phone is lost when ___. (a) you send a message (b) the phone is lost (c) the app is closed (d) the screen turns off
13. 13.True or false: the sound on/off setting fits saving on the phone. (a) False (b) True
14. 14.💾 What does this code show? (Positions start at 0.)
    let songs = ["Rain", "Stars", "Sunrise", "Kites", "Monsoon"];
    show(songs[0]); (a) Sunrise (b) Kites (c) Rain (d) Stars
15. 15.💾 What number does this code show?
    let coins = 6;
    coins = coins - 2;
    coins = coins + 3;
    show(coins);
16. 16.True or false: notes to read offline fits saving in the cloud. (a) True (b) False
17. 17.💾 What number does this code show?
    let score = 3;
    score = score - 3;
    score = score + 5;
    show(score);
18. 18.💾 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
19. 19.💾 What does this code show? (Positions start at 0.)
    let notes = ["Science", "Hindi", "Art", "Maths"];
    show(notes[3]); (a) Science (b) Art (c) Hindi (d) Maths
20. 20.💾 What number does this code show?
    let songs = ["Kites", "Sunrise", "Monsoon"];
    songs.push("Rain");
    show(songs.length);
21. 21.💾 What does this code show? (Positions start at 0.)
    let songs = ["Kites", "Stars", "Monsoon", "Ocean"];
    show(songs[1]); (a) Stars (b) Monsoon (c) Kites (d) Ocean
22. 22.💾 pop() takes off the last item. What does this code show?
    let friends = ["Aman", "Arjun", "Meera", "Zoya"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Aman (b) Arjun (c) Zoya (d) Meera
23. 23.Which of these fits saving on the phone? (a) your last game level (b) a class leaderboard (c) a shared to-do list (d) photos on two devices
24. 24.💾 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
25. 25.💾 What is a variable? (a) a named box for a value (b) a type of screen (c) a phone setting (d) a picture
26. 26.True or false: chat messages to friends fits saving in the cloud. (a) False (b) True
27. 27.💾 Where should the app save photos on two devices: on the phone or in the cloud? (a) in the cloud (b) on the phone
28. 28.💾 What number does this code show?
    let friends = ["Riya", "Aman"];
    friends.push("Zoya");
    friends.push("Kabir");
    show(friends.length);
29. 29.Which of these fits saving on the phone? (a) a class leaderboard (b) notes to read offline (c) photos on two devices (d) a shared to-do list
30. 30.💾 What number does this code show?
    let songs = ["Monsoon", "Sunrise"];
    songs.push("Ocean");
    songs.push("Rain");
    show(songs.length);
31. 31.💾 Which can hold many values in order? (a) a switch (b) a single number (c) a button (d) a list
32. 32.💾 What number does this code show?
    let notes = ["Maths", "Art"];
    notes.push("Hindi");
    show(notes.length);
33. 33.Which of these fits saving on the phone? (a) a draft you are typing (b) a shared to-do list (c) photos on two devices (d) a class leaderboard
34. 34.💾 What number does this code show?
    let notes = ["Science", "Sports", "Hindi"];
    notes.push("Maths");
    notes.push("Music");
    show(notes.length);
35. 35.Which of these fits saving in the cloud? (a) your last game level (b) a draft you are typing (c) notes to read offline (d) photos on two devices
36. 36.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) in the cloud (b) on the phone
37. 37.💾 What number does this code show?
    let friends = ["Zoya", "Riya", "Kabir"];
    friends.push("Arjun");
    friends.push("Aman");
    show(friends.length);
38. 38.True or false: a class leaderboard fits saving on the phone. (a) False (b) True
39. 39.💾 What number does this code show?
    let points = 4;
    points = points - 1;
    points = points + 5;
    show(points);
40. 40.💾 What does this code show? (Positions start at 0.)
    let songs = ["Ocean", "Monsoon", "Kites", "Sunrise"];
    show(songs[0]); (a) Monsoon (b) Ocean (c) Sunrise (d) Kites

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