App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 80 · 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 songs = ["Stars", "Rain"];
   songs.push("Monsoon");
   show(songs.length);
2. 2.💾 pop() takes off the last item. What does this code show?
   let songs = ["Kites", "Monsoon", "Stars", "Sunrise", "Ocean"];
   songs.pop();
   show(songs[songs.length - 1]); (a) Stars (b) Sunrise (c) Kites (d) Monsoon
3. 3.💾 What is a variable? (a) a picture (b) a type of screen (c) a phone setting (d) a named box for a value
4. 4.Which of these fits saving in the cloud? (a) chat messages to friends (b) the sound on/off setting (c) notes to read offline (d) your last game level
5. 5.True or false: a draft you are typing fits saving on the phone. (a) False (b) True
6. 6.💾 What number does this code show?
   let friends = ["Riya", "Zoya", "Aman"];
   friends.push("Kabir");
   friends.push("Arjun");
   show(friends.length);
7. 7.💾 What number does this code show?
   let score = 6;
   score = score - 4;
   score = score + 4;
   show(score);
8. 8.💾 What number does this code show?
   let friends = ["Zoya", "Arjun", "Aman", "Meera"];
   friends.push("Riya");
   friends.push("Kabir");
   show(friends.length);
9. 9.💾 pop() takes off the last item. What does this code show?
   let friends = ["Arjun", "Kabir", "Riya"];
   friends.pop();
   show(friends[friends.length - 1]); (a) Kabir (b) Arjun (c) Riya
10. 10.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) in the cloud (b) on the phone
11. 11.True or false: your last game level fits saving in the cloud. (a) True (b) False
12. 12.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) in the cloud (b) on the phone
13. 13.💾 What number does this code show?
    let songs = ["Rain", "Kites", "Stars"];
    songs.push("Sunrise");
    show(songs.length);
14. 14.💾 Where should the app save a shared to-do list: on the phone or in the cloud? (a) in the cloud (b) on the phone
15. 15.💾 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
16. 16.💾 Which works with no internet at all? (a) a cloud backup (b) data saved on the phone (c) a cloud leaderboard (d) a shared chat
17. 17.💾 What does this code show? (Positions start at 0.)
    let songs = ["Rain", "Stars", "Ocean"];
    show(songs[1]); (a) Stars (b) Rain (c) Ocean
18. 18.💾 What number does this code show?
    let friends = ["Aman", "Meera"];
    friends.push("Zoya");
    show(friends.length);
19. 19.💾 What number does this code show?
    let notes = ["Music", "Hindi"];
    notes.push("Art");
    show(notes.length);
20. 20.💾 pop() takes off the last item. What does this code show?
    let songs = ["Ocean", "Stars", "Rain"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Rain (b) Ocean (c) Stars
21. 21.💾 What does this code show? (Positions start at 0.)
    let notes = ["Maths", "Art", "Hindi"];
    show(notes[0]); (a) Art (b) Hindi (c) Maths
22. 22.💾 What number does this code show?
    let songs = ["Stars", "Sunrise", "Kites"];
    songs.push("Rain");
    show(songs.length);
23. 23.💾 What number does this code show?
    let coins = 6;
    coins = coins - 3;
    coins = coins + 5;
    show(coins);
24. 24.True or false: chat messages to friends fits saving in the cloud. (a) True (b) False
25. 25.💾 What number does this code show?
    let notes = ["Sports", "Maths", "Hindi", "Music"];
    notes.push("Art");
    notes.push("Science");
    show(notes.length);
26. 26.💾 What number does this code show?
    let songs = ["Monsoon", "Rain", "Kites", "Sunrise"];
    songs.push("Ocean");
    songs.push("Stars");
    show(songs.length);
27. 27.True or false: notes to read offline fits saving in the cloud. (a) True (b) False
28. 28.💾 Which can hold many values in order? (a) a switch (b) a button (c) a single number (d) a list
29. 29.True or false: notes to read offline fits saving on the phone. (a) True (b) False
30. 30.Which of these fits saving in the cloud? (a) notes to read offline (b) a draft you are typing (c) photos on two devices (d) the sound on/off setting
31. 31.True or false: a shared to-do list fits saving on the phone. (a) True (b) False
32. 32.💾 What does this code show? (Positions start at 0.)
    let songs = ["Ocean", "Kites", "Monsoon"];
    show(songs[0]); (a) Monsoon (b) Kites (c) Ocean
33. 33.💾 What number does this code show?
    let points = 4;
    points = points - 1;
    points = points + 5;
    show(points);
34. 34.💾 What number does this code show?
    let friends = ["Riya", "Kabir"];
    friends.push("Zoya");
    show(friends.length);
35. 35.Which of these fits saving in the cloud? (a) your last game level (b) a draft you are typing (c) a shared to-do list (d) the sound on/off setting
36. 36.💾 What number does this code show?
    let notes = ["Sports", "Hindi", "Science"];
    notes.push("Maths");
    show(notes.length);
37. 37.True or false: a shared to-do list fits saving in the cloud. (a) False (b) True
38. 38.💾 What does this code show? (Positions start at 0.)
    let friends = ["Kabir", "Zoya", "Riya"];
    show(friends[2]); (a) Zoya (b) Kabir (c) Riya
39. 39.💾 In most code, the first item of a list is at position ___. (a) 0 (b) 2 (c) 1 (d) 10
40. 40.💾 What number does this code show?
    let friends = ["Zoya", "Riya"];
    friends.push("Kabir");
    show(friends.length);

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