App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 359 · 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 score = 7;
   score = score - 3;
   score = score + 2;
   show(score);
2. 2.💾 Data saved only on the phone is lost when ___. (a) the app is closed (b) the screen turns off (c) you send a message (d) the phone is lost
3. 3.Which of these fits saving on the phone? (a) a class leaderboard (b) chat messages to friends (c) a draft you are typing (d) a shared to-do list
4. 4.💾 What number does this code show?
   let songs = ["Monsoon", "Kites", "Sunrise", "Rain"];
   songs.push("Ocean");
   show(songs.length);
5. 5.💾 What does this code show? (Positions start at 0.)
   let notes = ["Sports", "Science", "Maths"];
   show(notes[1]); (a) Science (b) Sports (c) Maths
6. 6.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) on the phone (b) in the cloud
7. 7.True or false: your last game level fits saving on the phone. (a) True (b) False
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 on the phone? (a) a shared to-do list (b) a class leaderboard (c) chat messages to friends (d) notes to read offline
10. 10.💾 What does this code show? (Positions start at 0.)
    let notes = ["Art", "Sports", "Hindi", "Science"];
    show(notes[1]); (a) Art (b) Science (c) Hindi (d) Sports
11. 11.💾 What number does this code show?
    let friends = ["Meera", "Aman", "Riya"];
    friends.push("Zoya");
    friends.push("Arjun");
    show(friends.length);
12. 12.💾 What number does this code show?
    let notes = ["Art", "Hindi", "Maths", "Science"];
    notes.push("Music");
    notes.push("Sports");
    show(notes.length);
13. 13.💾 pop() takes off the last item. What does this code show?
    let songs = ["Stars", "Kites", "Monsoon", "Sunrise", "Rain"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Stars (b) Monsoon (c) Sunrise (d) Kites
14. 14.Which of these fits saving in the cloud? (a) the sound on/off setting (b) your last game level (c) notes to read offline (d) photos on two devices
15. 15.True or false: a class leaderboard fits saving in the cloud. (a) True (b) False
16. 16.💾 What number does this code show?
    let coins = 3;
    coins = coins - 2;
    coins = coins + 3;
    show(coins);
17. 17.💾 What number does this code show?
    let score = 3;
    score = score - 3;
    score = score + 1;
    show(score);
18. 18.💾 What does this code show? (Positions start at 0.)
    let notes = ["Science", "Music", "Sports", "Hindi", "Art"];
    show(notes[3]); (a) Sports (b) Hindi (c) Music (d) Science
19. 19.True or false: chat messages to friends fits saving on the phone. (a) True (b) False
20. 20.💾 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
21. 21.💾 What does this code show? (Positions start at 0.)
    let songs = ["Ocean", "Sunrise", "Rain"];
    show(songs[0]); (a) Rain (b) Sunrise (c) Ocean
22. 22.💾 What does this code show? (Positions start at 0.)
    let friends = ["Aman", "Riya", "Kabir", "Zoya"];
    show(friends[1]); (a) Aman (b) Zoya (c) Kabir (d) Riya
23. 23.💾 What number does this code show?
    let stars = 5;
    stars = stars - 5;
    stars = stars + 2;
    show(stars);
24. 24.💾 Which works with no internet at all? (a) a cloud leaderboard (b) a shared chat (c) data saved on the phone (d) a cloud backup
25. 25.💾 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
26. 26.💾 pop() takes off the last item. What does this code show?
    let notes = ["Maths", "Science", "Art", "Music", "Sports"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Music (b) Art (c) Maths (d) Science
27. 27.💾 What number does this code show?
    let songs = ["Ocean", "Stars", "Monsoon", "Sunrise"];
    songs.push("Kites");
    show(songs.length);
28. 28.💾 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
29. 29.True or false: a shared to-do list fits saving in the cloud. (a) False (b) True
30. 30.💾 What number does this code show?
    let stars = 5;
    stars = stars - 4;
    stars = stars + 2;
    show(stars);
31. 31.💾 What does this code show? (Positions start at 0.)
    let friends = ["Arjun", "Aman", "Meera"];
    show(friends[1]); (a) Arjun (b) Meera (c) Aman
32. 32.💾 Where should the app save your last game level: on the phone or in the cloud? (a) in the cloud (b) on the phone
33. 33.Which of these fits saving on the phone? (a) chat messages to friends (b) the sound on/off setting (c) a shared to-do list (d) photos on two devices
34. 34.💾 Which can hold many values in order? (a) a switch (b) a button (c) a list (d) a single number
35. 35.💾 What does this code show? (Positions start at 0.)
    let notes = ["Music", "Maths", "Sports", "Science", "Hindi"];
    show(notes[2]); (a) Science (b) Maths (c) Sports (d) Music
36. 36.💾 In most code, the first item of a list is at position ___. (a) 1 (b) 2 (c) 0 (d) 10
37. 37.💾 What number does this code show?
    let notes = ["Sports", "Maths", "Science"];
    notes.push("Hindi");
    notes.push("Art");
    show(notes.length);
38. 38.💾 What does this code show? (Positions start at 0.)
    let notes = ["Science", "Maths", "Sports", "Hindi", "Art"];
    show(notes[4]); (a) Art (b) Maths (c) Science (d) Sports
39. 39.Which of these fits saving in the cloud? (a) the sound on/off setting (b) chat messages to friends (c) notes to read offline (d) your last game level
40. 40.Which of these fits saving in the cloud? (a) a draft you are typing (b) notes to read offline (c) a shared to-do list (d) your last game level

Free app development lessons, practice and worksheets at talentjr.in/app-development-for-students