App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 812 · 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.💾 pop() takes off the last item. What does this code show?
   let notes = ["Music", "Hindi", "Sports"];
   notes.pop();
   show(notes[notes.length - 1]); (a) Hindi (b) Music (c) Sports
2. 2.💾 Data saved only on the phone is lost when ___. (a) the app is closed (b) you send a message (c) the phone is lost (d) the screen turns off
3. 3.💾 In most code, the first item of a list is at position ___. (a) 1 (b) 10 (c) 0 (d) 2
4. 4.💾 What number does this code show?
   let friends = ["Arjun", "Aman"];
   friends.push("Zoya");
   friends.push("Riya");
   show(friends.length);
5. 5.True or false: the sound on/off setting fits saving on the phone. (a) False (b) True
6. 6.True or false: notes to read offline fits saving in the cloud. (a) True (b) False
7. 7.💾 What number does this code show?
   let notes = ["Music", "Hindi", "Sports", "Science"];
   notes.push("Maths");
   show(notes.length);
8. 8.💾 What does this code show? (Positions start at 0.)
   let friends = ["Aman", "Riya", "Zoya"];
   show(friends[0]); (a) Aman (b) Zoya (c) Riya
9. 9.💾 What number does this code show?
   let points = 9;
   points = points - 8;
   points = points + 5;
   show(points);
10. 10.💾 Where should the app save photos on two devices: on the phone or in the cloud? (a) on the phone (b) in the cloud
11. 11.💾 What number does this code show?
    let songs = ["Kites", "Monsoon"];
    songs.push("Sunrise");
    songs.push("Rain");
    show(songs.length);
12. 12.💾 What number does this code show?
    let friends = ["Aman", "Arjun", "Meera", "Riya"];
    friends.push("Kabir");
    show(friends.length);
13. 13.💾 pop() takes off the last item. What does this code show?
    let songs = ["Sunrise", "Rain", "Ocean", "Kites", "Stars"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Ocean (b) Rain (c) Sunrise (d) Kites
14. 14.💾 What does this code show? (Positions start at 0.)
    let notes = ["Science", "Art", "Hindi"];
    show(notes[0]); (a) Art (b) Hindi (c) Science
15. 15.True or false: notes to read offline fits saving on the phone. (a) False (b) True
16. 16.Which of these fits saving in the cloud? (a) a draft you are typing (b) a class leaderboard (c) the sound on/off setting (d) notes to read offline
17. 17.💾 What does this code show? (Positions start at 0.)
    let friends = ["Zoya", "Aman", "Arjun", "Meera", "Riya"];
    show(friends[4]); (a) Aman (b) Zoya (c) Arjun (d) Riya
18. 18.💾 Which can hold many values in order? (a) a button (b) a single number (c) a switch (d) a list
19. 19.💾 What does this code show? (Positions start at 0.)
    let friends = ["Riya", "Zoya", "Arjun", "Kabir"];
    show(friends[1]); (a) Kabir (b) Riya (c) Zoya (d) Arjun
20. 20.💾 What number does this code show?
    let notes = ["Science", "Art"];
    notes.push("Maths");
    show(notes.length);
21. 21.💾 What number does this code show?
    let score = 4;
    score = score - 1;
    score = score + 4;
    show(score);
22. 22.True or false: the sound on/off setting fits saving in the cloud. (a) True (b) False
23. 23.Which of these fits saving on the phone? (a) a class leaderboard (b) notes to read offline (c) a shared to-do list (d) photos on two devices
24. 24.True or false: chat messages to friends fits saving in the cloud. (a) False (b) True
25. 25.💾 Where should the app save notes to read offline: on the phone or in the cloud? (a) on the phone (b) in the cloud
26. 26.True or false: a shared to-do list fits saving on the phone. (a) False (b) True
27. 27.💾 pop() takes off the last item. What does this code show?
    let friends = ["Aman", "Zoya", "Kabir", "Arjun"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Aman (b) Kabir (c) Zoya (d) Arjun
28. 28.💾 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
29. 29.💾 What number does this code show?
    let lives = 6;
    lives = lives - 2;
    lives = lives + 2;
    show(lives);
30. 30.Which of these fits saving on the phone? (a) the sound on/off setting (b) a shared to-do list (c) photos on two devices (d) chat messages to friends
31. 31.💾 What number does this code show?
    let friends = ["Aman", "Zoya"];
    friends.push("Arjun");
    friends.push("Meera");
    show(friends.length);
32. 32.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) on the phone (b) in the cloud
33. 33.Which of these fits saving in the cloud? (a) a draft you are typing (b) notes to read offline (c) your last game level (d) a shared to-do list
34. 34.💾 What number does this code show?
    let lives = 4;
    lives = lives - 2;
    lives = lives + 1;
    show(lives);
35. 35.💾 What does this code show? (Positions start at 0.)
    let notes = ["Science", "Maths", "Music", "Art", "Hindi"];
    show(notes[0]); (a) Maths (b) Art (c) Music (d) Science
36. 36.💾 What number does this code show?
    let points = 5;
    points = points - 2;
    points = points + 3;
    show(points);
37. 37.💾 What number does this code show?
    let friends = ["Aman", "Arjun", "Meera"];
    friends.push("Zoya");
    show(friends.length);
38. 38.💾 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
39. 39.Which of these fits saving in the cloud? (a) the sound on/off setting (b) notes to read offline (c) photos on two devices (d) your last game level
40. 40.True or false: a shared to-do list fits saving in the cloud. (a) False (b) True

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