App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 483 · 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 = ["Maths", "Sports", "Science", "Art"];
   notes.push("Music");
   notes.push("Hindi");
   show(notes.length);
2. 2.💾 What number does this code show?
   let notes = ["Music", "Hindi"];
   notes.push("Art");
   notes.push("Science");
   show(notes.length);
3. 3.💾 What does this code show? (Positions start at 0.)
   let songs = ["Kites", "Ocean", "Monsoon", "Rain"];
   show(songs[3]); (a) Kites (b) Monsoon (c) Rain (d) Ocean
4. 4.💾 What number does this code show?
   let songs = ["Ocean", "Stars", "Kites", "Rain"];
   songs.push("Monsoon");
   show(songs.length);
5. 5.💾 What number does this code show?
   let coins = 7;
   coins = coins - 6;
   coins = coins + 1;
   show(coins);
6. 6.Which of these fits saving in the cloud? (a) notes to read offline (b) your last game level (c) chat messages to friends (d) a draft you are typing
7. 7.Which of these fits saving in the cloud? (a) a class leaderboard (b) a draft you are typing (c) notes to read offline (d) the sound on/off setting
8. 8.💾 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
9. 9.💾 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
10. 10.💾 What number does this code show?
    let coins = 4;
    coins = coins - 2;
    coins = coins + 1;
    show(coins);
11. 11.💾 What does this code show? (Positions start at 0.)
    let friends = ["Meera", "Kabir", "Riya", "Arjun", "Aman"];
    show(friends[3]); (a) Kabir (b) Meera (c) Arjun (d) Riya
12. 12.💾 What is a variable? (a) a type of screen (b) a phone setting (c) a picture (d) a named box for a value
13. 13.💾 What number does this code show?
    let coins = 6;
    coins = coins - 6;
    coins = coins + 3;
    show(coins);
14. 14.True or false: your last game level fits saving on the phone. (a) False (b) True
15. 15.💾 Which works with no internet at all? (a) a cloud backup (b) a shared chat (c) a cloud leaderboard (d) data saved on the phone
16. 16.💾 Where should the app save photos on two devices: on the phone or in the cloud? (a) in the cloud (b) on the phone
17. 17.Which of these fits saving on the phone? (a) a class leaderboard (b) chat messages to friends (c) your last game level (d) photos on two devices
18. 18.True or false: notes to read offline fits saving on the phone. (a) False (b) True
19. 19.💾 What does this code show? (Positions start at 0.)
    let friends = ["Meera", "Aman", "Riya", "Kabir"];
    show(friends[0]); (a) Riya (b) Kabir (c) Aman (d) Meera
20. 20.💾 What number does this code show?
    let lives = 6;
    lives = lives - 1;
    lives = lives + 4;
    show(lives);
21. 21.Which of these fits saving on the phone? (a) chat messages to friends (b) a class leaderboard (c) a shared to-do list (d) the sound on/off setting
22. 22.💾 What number does this code show?
    let songs = ["Sunrise", "Monsoon", "Rain"];
    songs.push("Kites");
    songs.push("Stars");
    show(songs.length);
23. 23.True or false: your last game level fits saving in the cloud. (a) True (b) False
24. 24.💾 What number does this code show?
    let lives = 5;
    lives = lives - 3;
    lives = lives + 1;
    show(lives);
25. 25.💾 pop() takes off the last item. What does this code show?
    let notes = ["Science", "Sports", "Hindi", "Maths"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Maths (b) Sports (c) Science (d) Hindi
26. 26.True or false: chat messages to friends fits saving in the cloud. (a) True (b) False
27. 27.💾 Which can hold many values in order? (a) a button (b) a switch (c) a list (d) a single number
28. 28.💾 What number does this code show?
    let coins = 5;
    coins = coins - 1;
    coins = coins + 5;
    show(coins);
29. 29.💾 What number does this code show?
    let coins = 8;
    coins = coins - 2;
    coins = coins + 2;
    show(coins);
30. 30.💾 What does this code show? (Positions start at 0.)
    let songs = ["Monsoon", "Rain", "Sunrise", "Ocean"];
    show(songs[0]); (a) Rain (b) Ocean (c) Monsoon (d) Sunrise
31. 31.💾 What number does this code show?
    let coins = 7;
    coins = coins - 1;
    coins = coins + 3;
    show(coins);
32. 32.💾 What number does this code show?
    let songs = ["Monsoon", "Kites"];
    songs.push("Stars");
    songs.push("Rain");
    show(songs.length);
33. 33.Which of these fits saving in the cloud? (a) the sound on/off setting (b) photos on two devices (c) your last game level (d) notes to read offline
34. 34.💾 What number does this code show?
    let stars = 9;
    stars = stars - 9;
    stars = stars + 1;
    show(stars);
35. 35.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) on the phone (b) in the cloud
36. 36.💾 What number does this code show?
    let friends = ["Meera", "Riya"];
    friends.push("Aman");
    friends.push("Kabir");
    show(friends.length);
37. 37.💾 What number does this code show?
    let notes = ["Music", "Art", "Maths", "Sports"];
    notes.push("Science");
    show(notes.length);
38. 38.💾 What number does this code show?
    let friends = ["Arjun", "Zoya", "Riya"];
    friends.push("Meera");
    show(friends.length);
39. 39.💾 What number does this code show?
    let points = 6;
    points = points - 4;
    points = points + 1;
    show(points);
40. 40.💾 Data saved only on the phone is lost when ___. (a) the screen turns off (b) you send a message (c) the phone is lost (d) the app is closed

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