App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 502 · 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.💾 Data saved only on the phone is lost when ___. (a) the phone is lost (b) the screen turns off (c) you send a message (d) the app is closed
2. 2.💾 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
3. 3.💾 What number does this code show?
   let songs = ["Sunrise", "Rain"];
   songs.push("Kites");
   songs.push("Ocean");
   show(songs.length);
4. 4.True or false: photos on two devices fits saving on the phone. (a) False (b) True
5. 5.Which of these fits saving on the phone? (a) chat messages to friends (b) a draft you are typing (c) photos on two devices (d) a class leaderboard
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.💾 pop() takes off the last item. What does this code show?
   let friends = ["Kabir", "Riya", "Zoya"];
   friends.pop();
   show(friends[friends.length - 1]); (a) Zoya (b) Kabir (c) Riya
8. 8.💾 Where should the app save photos on two devices: on the phone or in the cloud? (a) in the cloud (b) on the phone
9. 9.💾 What number does this code show?
   let score = 4;
   score = score - 3;
   score = score + 2;
   show(score);
10. 10.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) on the phone (b) in the cloud
11. 11.💾 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
12. 12.💾 What does this code show? (Positions start at 0.)
    let songs = ["Stars", "Kites", "Rain"];
    show(songs[2]); (a) Stars (b) Kites (c) Rain
13. 13.True or false: notes to read offline fits saving in the cloud. (a) True (b) False
14. 14.True or false: a class leaderboard fits saving on the phone. (a) True (b) False
15. 15.💾 Which can hold many values in order? (a) a button (b) a single number (c) a switch (d) a list
16. 16.💾 What number does this code show?
    let notes = ["Hindi", "Art", "Sports"];
    notes.push("Science");
    notes.push("Music");
    show(notes.length);
17. 17.💾 pop() takes off the last item. What does this code show?
    let songs = ["Sunrise", "Stars", "Kites", "Ocean"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Stars (b) Kites (c) Ocean (d) Sunrise
18. 18.💾 What number does this code show?
    let friends = ["Kabir", "Arjun"];
    friends.push("Zoya");
    show(friends.length);
19. 19.💾 pop() takes off the last item. What does this code show?
    let friends = ["Meera", "Kabir", "Aman", "Riya"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Aman (b) Kabir (c) Riya (d) Meera
20. 20.Which of these fits saving on the phone? (a) chat messages to friends (b) a class leaderboard (c) the sound on/off setting (d) a shared to-do list
21. 21.💾 What does this code show? (Positions start at 0.)
    let notes = ["Maths", "Music", "Hindi", "Science", "Sports"];
    show(notes[0]); (a) Music (b) Maths (c) Science (d) Hindi
22. 22.💾 What does this code show? (Positions start at 0.)
    let notes = ["Sports", "Music", "Hindi", "Science", "Maths"];
    show(notes[4]); (a) Hindi (b) Maths (c) Music (d) Sports
23. 23.True or false: a draft you are typing fits saving in the cloud. (a) True (b) False
24. 24.💾 What does this code show? (Positions start at 0.)
    let songs = ["Monsoon", "Rain", "Stars"];
    show(songs[1]); (a) Rain (b) Monsoon (c) Stars
25. 25.💾 What is a variable? (a) a phone setting (b) a picture (c) a type of screen (d) a named box for a value
26. 26.💾 In most code, the first item of a list is at position ___. (a) 0 (b) 1 (c) 10 (d) 2
27. 27.💾 What does this code show? (Positions start at 0.)
    let notes = ["Music", "Maths", "Art"];
    show(notes[1]); (a) Maths (b) Art (c) Music
28. 28.True or false: chat messages to friends fits saving on the phone. (a) True (b) False
29. 29.💾 Which works with no internet at all? (a) a cloud backup (b) a shared chat (c) data saved on the phone (d) a cloud leaderboard
30. 30.💾 pop() takes off the last item. What does this code show?
    let notes = ["Sports", "Maths", "Music"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Sports (b) Music (c) Maths
31. 31.True or false: a shared to-do list fits saving on the phone. (a) True (b) False
32. 32.True or false: photos on two devices fits saving in the cloud. (a) True (b) False
33. 33.💾 What does this code show? (Positions start at 0.)
    let songs = ["Sunrise", "Stars", "Ocean", "Monsoon"];
    show(songs[1]); (a) Stars (b) Ocean (c) Monsoon (d) Sunrise
34. 34.💾 What number does this code show?
    let notes = ["Science", "Sports", "Music", "Hindi"];
    notes.push("Maths");
    notes.push("Art");
    show(notes.length);
35. 35.💾 What number does this code show?
    let songs = ["Kites", "Monsoon", "Sunrise"];
    songs.push("Ocean");
    show(songs.length);
36. 36.💾 What does this code show? (Positions start at 0.)
    let songs = ["Ocean", "Stars", "Rain", "Monsoon"];
    show(songs[1]); (a) Rain (b) Stars (c) Monsoon (d) Ocean
37. 37.💾 pop() takes off the last item. What does this code show?
    let songs = ["Sunrise", "Rain", "Monsoon", "Ocean"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Monsoon (b) Ocean (c) Rain (d) Sunrise
38. 38.Which of these fits saving on the phone? (a) photos on two devices (b) a shared to-do list (c) a class leaderboard (d) your last game level
39. 39.💾 What number does this code show?
    let songs = ["Kites", "Monsoon"];
    songs.push("Ocean");
    show(songs.length);
40. 40.💾 What number does this code show?
    let songs = ["Sunrise", "Ocean", "Rain", "Stars"];
    songs.push("Monsoon");
    show(songs.length);

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