App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 841 · 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 points = 4;
   points = points - 4;
   points = points + 5;
   show(points);
2. 2.💾 What number does this code show?
   let score = 6;
   score = score - 5;
   score = score + 1;
   show(score);
3. 3.💾 Where should the app save the sound on/off setting: on the phone or in the cloud? (a) in the cloud (b) on the phone
4. 4.💾 Which can hold many values in order? (a) a list (b) a single number (c) a button (d) a switch
5. 5.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) on the phone (b) in the cloud
6. 6.💾 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
7. 7.True or false: the sound on/off setting fits saving in the cloud. (a) True (b) False
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 notes = ["Music", "Science"];
   notes.push("Maths");
   show(notes.length);
10. 10.💾 What is a variable? (a) a picture (b) a type of screen (c) a phone setting (d) a named box for a value
11. 11.💾 What does this code show? (Positions start at 0.)
    let friends = ["Arjun", "Aman", "Riya", "Zoya"];
    show(friends[1]); (a) Arjun (b) Zoya (c) Riya (d) Aman
12. 12.True or false: notes to read offline fits saving on the phone. (a) False (b) True
13. 13.💾 What number does this code show?
    let coins = 3;
    coins = coins - 1;
    coins = coins + 4;
    show(coins);
14. 14.💾 pop() takes off the last item. What does this code show?
    let songs = ["Ocean", "Sunrise", "Monsoon", "Kites", "Rain"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Kites (b) Monsoon (c) Sunrise (d) Ocean
15. 15.True or false: photos on two devices fits saving on the phone. (a) False (b) True
16. 16.💾 What number does this code show?
    let notes = ["Maths", "Art", "Music", "Science"];
    notes.push("Hindi");
    show(notes.length);
17. 17.True or false: photos on two devices fits saving in the cloud. (a) True (b) False
18. 18.💾 What number does this code show?
    let notes = ["Science", "Sports"];
    notes.push("Hindi");
    notes.push("Art");
    show(notes.length);
19. 19.💾 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
20. 20.💾 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
21. 21.💾 pop() takes off the last item. What does this code show?
    let friends = ["Arjun", "Riya", "Aman", "Kabir", "Zoya"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Arjun (b) Riya (c) Kabir (d) Aman
22. 22.💾 pop() takes off the last item. What does this code show?
    let songs = ["Sunrise", "Stars", "Monsoon", "Ocean"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Stars (b) Sunrise (c) Ocean (d) Monsoon
23. 23.💾 What number does this code show?
    let lives = 5;
    lives = lives - 5;
    lives = lives + 2;
    show(lives);
24. 24.💾 What number does this code show?
    let notes = ["Hindi", "Music", "Art"];
    notes.push("Science");
    notes.push("Maths");
    show(notes.length);
25. 25.💾 Data saved only on the phone is lost when ___. (a) the phone is lost (b) the app is closed (c) the screen turns off (d) you send a message
26. 26.Which of these fits saving on the phone? (a) chat messages to friends (b) a shared to-do list (c) the sound on/off setting (d) photos on two devices
27. 27.💾 What number does this code show?
    let lives = 4;
    lives = lives - 1;
    lives = lives + 4;
    show(lives);
28. 28.💾 What does this code show? (Positions start at 0.)
    let notes = ["Maths", "Sports", "Science", "Hindi"];
    show(notes[2]); (a) Science (b) Maths (c) Sports (d) Hindi
29. 29.💾 pop() takes off the last item. What does this code show?
    let friends = ["Aman", "Zoya", "Meera", "Arjun", "Riya"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Arjun (b) Aman (c) Zoya (d) Meera
30. 30.True or false: a class leaderboard fits saving in the cloud. (a) False (b) True
31. 31.💾 What number does this code show?
    let friends = ["Meera", "Riya"];
    friends.push("Zoya");
    show(friends.length);
32. 32.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
33. 33.Which of these fits saving in the cloud? (a) the sound on/off setting (b) notes to read offline (c) your last game level (d) a class leaderboard
34. 34.💾 In most code, the first item of a list is at position ___. (a) 2 (b) 1 (c) 10 (d) 0
35. 35.True or false: notes to read offline fits saving in the cloud. (a) False (b) True
36. 36.True or false: a shared to-do list fits saving in the cloud. (a) True (b) False
37. 37.Which of these fits saving in the cloud? (a) your last game level (b) the sound on/off setting (c) chat messages to friends (d) notes to read offline
38. 38.💾 pop() takes off the last item. What does this code show?
    let notes = ["Maths", "Hindi", "Art", "Sports"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Maths (b) Hindi (c) Art (d) Sports
39. 39.Which of these fits saving on the phone? (a) photos on two devices (b) a class leaderboard (c) a shared to-do list (d) your last game level
40. 40.💾 What number does this code show?
    let notes = ["Music", "Sports"];
    notes.push("Science");
    notes.push("Art");
    show(notes.length);

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