App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 991 · 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 = ["Art", "Music", "Sports", "Maths"];
   notes.push("Science");
   show(notes.length);
2. 2.💾 What is a variable? (a) a type of screen (b) a named box for a value (c) a picture (d) a phone setting
3. 3.💾 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
4. 4.💾 What number does this code show?
   let notes = ["Maths", "Science", "Art", "Music"];
   notes.push("Hindi");
   notes.push("Sports");
   show(notes.length);
5. 5.True or false: notes to read offline fits saving in the cloud. (a) True (b) False
6. 6.💾 What does this code show? (Positions start at 0.)
   let notes = ["Art", "Hindi", "Science", "Sports", "Music"];
   show(notes[1]); (a) Art (b) Sports (c) Hindi (d) Science
7. 7.Which of these fits saving on the phone? (a) chat messages to friends (b) photos on two devices (c) a class leaderboard (d) a draft you are typing
8. 8.💾 Which can hold many values in order? (a) a single number (b) a list (c) a switch (d) a button
9. 9.True or false: a class leaderboard fits saving on the phone. (a) True (b) False
10. 10.Which of these fits saving in the cloud? (a) your last game level (b) the sound on/off setting (c) chat messages to friends (d) notes to read offline
11. 11.True or false: your last game level fits saving in the cloud. (a) False (b) True
12. 12.True or false: a shared to-do list fits saving on the phone. (a) True (b) False
13. 13.💾 What does this code show? (Positions start at 0.)
    let friends = ["Arjun", "Riya", "Meera"];
    show(friends[0]); (a) Arjun (b) Riya (c) Meera
14. 14.💾 What does this code show? (Positions start at 0.)
    let songs = ["Rain", "Monsoon", "Sunrise"];
    show(songs[2]); (a) Monsoon (b) Sunrise (c) Rain
15. 15.💾 What number does this code show?
    let songs = ["Ocean", "Rain", "Sunrise", "Stars"];
    songs.push("Monsoon");
    songs.push("Kites");
    show(songs.length);
16. 16.True or false: a draft you are typing fits saving in the cloud. (a) False (b) True
17. 17.💾 What number does this code show?
    let coins = 3;
    coins = coins - 3;
    coins = coins + 5;
    show(coins);
18. 18.Which of these fits saving in the cloud? (a) a shared to-do list (b) notes to read offline (c) your last game level (d) a draft you are typing
19. 19.💾 What does this code show? (Positions start at 0.)
    let notes = ["Science", "Maths", "Hindi", "Music", "Art"];
    show(notes[2]); (a) Hindi (b) Science (c) Maths (d) Music
20. 20.💾 pop() takes off the last item. What does this code show?
    let friends = ["Zoya", "Arjun", "Aman", "Riya", "Meera"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Zoya (b) Riya (c) Aman (d) Arjun
21. 21.💾 Saving data in the cloud lets you ___. (a) never need a password (b) shrink the app (c) use it on any device (d) skip the internet
22. 22.Which of these fits saving on the phone? (a) a shared to-do list (b) your last game level (c) photos on two devices (d) chat messages to friends
23. 23.💾 What does this code show? (Positions start at 0.)
    let songs = ["Sunrise", "Rain", "Stars", "Monsoon"];
    show(songs[2]); (a) Rain (b) Monsoon (c) Stars (d) Sunrise
24. 24.💾 What number does this code show?
    let points = 5;
    points = points - 1;
    points = points + 2;
    show(points);
25. 25.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) in the cloud (b) on the phone
26. 26.True or false: the sound on/off setting fits saving in the cloud. (a) True (b) False
27. 27.💾 What does this code show? (Positions start at 0.)
    let notes = ["Sports", "Art", "Science", "Music", "Maths"];
    show(notes[1]); (a) Art (b) Science (c) Sports (d) Music
28. 28.Which of these fits saving in the cloud? (a) notes to read offline (b) photos on two devices (c) a draft you are typing (d) the sound on/off setting
29. 29.True or false: the sound on/off setting fits saving on the phone. (a) False (b) True
30. 30.💾 pop() takes off the last item. What does this code show?
    let notes = ["Maths", "Art", "Sports", "Hindi"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Sports (b) Hindi (c) Maths (d) Art
31. 31.💾 What does this code show? (Positions start at 0.)
    let friends = ["Riya", "Zoya", "Meera"];
    show(friends[1]); (a) Meera (b) Riya (c) Zoya
32. 32.💾 What does this code show? (Positions start at 0.)
    let notes = ["Hindi", "Maths", "Sports", "Music"];
    show(notes[3]); (a) Music (b) Hindi (c) Sports (d) Maths
33. 33.💾 What number does this code show?
    let stars = 3;
    stars = stars - 2;
    stars = stars + 4;
    show(stars);
34. 34.💾 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
35. 35.💾 What number does this code show?
    let songs = ["Kites", "Ocean", "Rain"];
    songs.push("Sunrise");
    show(songs.length);
36. 36.Which of these fits saving on the phone? (a) a shared to-do list (b) the sound on/off setting (c) chat messages to friends (d) a class leaderboard
37. 37.True or false: chat messages to friends fits saving on the phone. (a) True (b) False
38. 38.True or false: your last game level fits saving on the phone. (a) True (b) False
39. 39.💾 What number does this code show?
    let lives = 9;
    lives = lives - 9;
    lives = lives + 4;
    show(lives);
40. 40.💾 What number does this code show?
    let notes = ["Music", "Sports", "Science", "Maths"];
    notes.push("Art");
    notes.push("Hindi");
    show(notes.length);

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