App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 545 · 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 = ["Science", "Maths", "Art"];
   notes.push("Music");
   notes.push("Sports");
   show(notes.length);
2. 2.💾 What number does this code show?
   let notes = ["Science", "Maths", "Music", "Sports"];
   notes.push("Art");
   show(notes.length);
3. 3.💾 What is a variable? (a) a type of screen (b) a picture (c) a named box for a value (d) a phone setting
4. 4.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
5. 5.💾 pop() takes off the last item. What does this code show?
   let songs = ["Monsoon", "Kites", "Sunrise", "Rain", "Stars"];
   songs.pop();
   show(songs[songs.length - 1]); (a) Sunrise (b) Rain (c) Kites (d) Monsoon
6. 6.True or false: a class leaderboard fits saving on the phone. (a) True (b) False
7. 7.💾 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
8. 8.💾 Which works with no internet at all? (a) a shared chat (b) a cloud leaderboard (c) data saved on the phone (d) a cloud backup
9. 9.💾 Where should the app save photos on two devices: on the phone or in the cloud? (a) in the cloud (b) on the phone
10. 10.💾 What number does this code show?
    let points = 3;
    points = points - 3;
    points = points + 4;
    show(points);
11. 11.💾 What number does this code show?
    let notes = ["Art", "Maths", "Hindi"];
    notes.push("Sports");
    show(notes.length);
12. 12.💾 What does this code show? (Positions start at 0.)
    let friends = ["Aman", "Riya", "Zoya", "Arjun", "Meera"];
    show(friends[4]); (a) Aman (b) Riya (c) Meera (d) Zoya
13. 13.True or false: chat messages to friends fits saving on the phone. (a) True (b) False
14. 14.Which of these fits saving on the phone? (a) a class leaderboard (b) a draft you are typing (c) chat messages to friends (d) a shared to-do list
15. 15.True or false: photos on two devices fits saving in the cloud. (a) True (b) False
16. 16.Which of these fits saving in the cloud? (a) your last game level (b) a draft you are typing (c) chat messages to friends (d) the sound on/off setting
17. 17.True or false: photos on two devices fits saving on the phone. (a) False (b) True
18. 18.💾 Which can hold many values in order? (a) a button (b) a single number (c) a list (d) a switch
19. 19.💾 pop() takes off the last item. What does this code show?
    let notes = ["Sports", "Maths", "Art", "Hindi", "Science"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Art (b) Hindi (c) Maths (d) Sports
20. 20.Which of these fits saving on the phone? (a) a shared to-do list (b) the sound on/off setting (c) a class leaderboard (d) photos on two devices
21. 21.Which of these fits saving in the cloud? (a) your last game level (b) the sound on/off setting (c) a shared to-do list (d) notes to read offline
22. 22.💾 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
23. 23.💾 What number does this code show?
    let friends = ["Zoya", "Arjun", "Riya", "Meera"];
    friends.push("Kabir");
    show(friends.length);
24. 24.💾 What number does this code show?
    let friends = ["Riya", "Arjun"];
    friends.push("Kabir");
    friends.push("Aman");
    show(friends.length);
25. 25.💾 What number does this code show?
    let songs = ["Ocean", "Monsoon"];
    songs.push("Kites");
    songs.push("Stars");
    show(songs.length);
26. 26.💾 pop() takes off the last item. What does this code show?
    let songs = ["Stars", "Sunrise", "Kites", "Ocean"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Ocean (b) Sunrise (c) Stars (d) Kites
27. 27.Which of these fits saving on the phone? (a) your last game level (b) a class leaderboard (c) chat messages to friends (d) photos on two devices
28. 28.💾 pop() takes off the last item. What does this code show?
    let notes = ["Science", "Art", "Hindi", "Maths"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Science (b) Hindi (c) Art (d) Maths
29. 29.💾 What number does this code show?
    let friends = ["Riya", "Arjun", "Zoya", "Kabir"];
    friends.push("Meera");
    show(friends.length);
30. 30.💾 Saving data in the cloud lets you ___. (a) never need a password (b) use it on any device (c) skip the internet (d) shrink the app
31. 31.💾 In most code, the first item of a list is at position ___. (a) 1 (b) 2 (c) 10 (d) 0
32. 32.💾 What does this code show? (Positions start at 0.)
    let friends = ["Aman", "Meera", "Kabir"];
    show(friends[1]); (a) Aman (b) Meera (c) Kabir
33. 33.Which of these fits saving in the cloud? (a) photos on two devices (b) a draft you are typing (c) notes to read offline (d) the sound on/off setting
34. 34.💾 Where should the app save notes to read offline: on the phone or in the cloud? (a) on the phone (b) in the cloud
35. 35.True or false: a draft you are typing fits saving in the cloud. (a) True (b) False
36. 36.💾 What number does this code show?
    let notes = ["Sports", "Science"];
    notes.push("Art");
    notes.push("Music");
    show(notes.length);
37. 37.💾 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
38. 38.💾 Where should the app save your last game level: on the phone or in the cloud? (a) in the cloud (b) on the phone
39. 39.💾 What number does this code show?
    let score = 7;
    score = score - 1;
    score = score + 1;
    show(score);
40. 40.💾 What number does this code show?
    let stars = 4;
    stars = stars - 2;
    stars = stars + 1;
    show(stars);

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