App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 142 · 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 friends = ["Aman", "Arjun", "Zoya", "Meera"];
   friends.push("Kabir");
   friends.push("Riya");
   show(friends.length);
2. 2.💾 What number does this code show?
   let friends = ["Aman", "Riya", "Meera", "Arjun"];
   friends.push("Zoya");
   friends.push("Kabir");
   show(friends.length);
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.💾 pop() takes off the last item. What does this code show?
   let notes = ["Hindi", "Art", "Sports"];
   notes.pop();
   show(notes[notes.length - 1]); (a) Hindi (b) Sports (c) Art
5. 5.💾 What number does this code show?
   let lives = 4;
   lives = lives - 1;
   lives = lives + 5;
   show(lives);
6. 6.True or false: notes to read offline fits saving in the cloud. (a) False (b) True
7. 7.💾 pop() takes off the last item. What does this code show?
   let notes = ["Sports", "Art", "Hindi", "Maths"];
   notes.pop();
   show(notes[notes.length - 1]); (a) Art (b) Sports (c) Maths (d) Hindi
8. 8.💾 What does this code show? (Positions start at 0.)
   let songs = ["Ocean", "Kites", "Rain", "Sunrise", "Stars"];
   show(songs[0]); (a) Sunrise (b) Kites (c) Ocean (d) Rain
9. 9.True or false: the sound on/off setting fits saving on the phone. (a) False (b) True
10. 10.💾 What is a variable? (a) a picture (b) a phone setting (c) a named box for a value (d) a type of screen
11. 11.💾 Where should the app save a class leaderboard: on the phone or in the cloud? (a) in the cloud (b) on the phone
12. 12.💾 What does this code show? (Positions start at 0.)
    let songs = ["Monsoon", "Rain", "Ocean"];
    show(songs[2]); (a) Ocean (b) Rain (c) Monsoon
13. 13.💾 What does this code show? (Positions start at 0.)
    let notes = ["Maths", "Sports", "Music"];
    show(notes[0]); (a) Music (b) Sports (c) Maths
14. 14.💾 What number does this code show?
    let friends = ["Kabir", "Riya", "Aman"];
    friends.push("Meera");
    friends.push("Zoya");
    show(friends.length);
15. 15.True or false: a shared to-do list fits saving on the phone. (a) True (b) False
16. 16.True or false: chat messages to friends fits saving in the cloud. (a) True (b) False
17. 17.💾 What does this code show? (Positions start at 0.)
    let friends = ["Aman", "Meera", "Riya"];
    show(friends[2]); (a) Riya (b) Meera (c) Aman
18. 18.💾 Where should the app save notes to read offline: on the phone or in the cloud? (a) on the phone (b) in the cloud
19. 19.True or false: notes to read offline fits saving on the phone. (a) True (b) False
20. 20.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) in the cloud (b) on the phone
21. 21.Which of these fits saving on the phone? (a) a class leaderboard (b) notes to read offline (c) chat messages to friends (d) photos on two devices
22. 22.💾 What number does this code show?
    let stars = 6;
    stars = stars - 3;
    stars = stars + 1;
    show(stars);
23. 23.Which of these fits saving on the phone? (a) a class leaderboard (b) your last game level (c) chat messages to friends (d) a shared to-do list
24. 24.💾 Where should the app save your last game level: on the phone or in the cloud? (a) in the cloud (b) on the phone
25. 25.True or false: photos on two devices fits saving in the cloud. (a) True (b) False
26. 26.💾 In most code, the first item of a list is at position ___. (a) 0 (b) 1 (c) 10 (d) 2
27. 27.💾 Where should the app save photos on two devices: on the phone or in the cloud? (a) on the phone (b) in the cloud
28. 28.💾 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
29. 29.💾 What number does this code show?
    let friends = ["Arjun", "Meera", "Kabir"];
    friends.push("Zoya");
    show(friends.length);
30. 30.💾 Which works with no internet at all? (a) a cloud leaderboard (b) a cloud backup (c) a shared chat (d) data saved on the phone
31. 31.True or false: photos on two devices fits saving on the phone. (a) True (b) False
32. 32.💾 Saving data in the cloud lets you ___. (a) skip the internet (b) use it on any device (c) shrink the app (d) never need a password
33. 33.💾 Data saved only on the phone is lost when ___. (a) you send a message (b) the app is closed (c) the phone is lost (d) the screen turns off
34. 34.💾 What number does this code show?
    let coins = 9;
    coins = coins - 6;
    coins = coins + 3;
    show(coins);
35. 35.💾 What does this code show? (Positions start at 0.)
    let friends = ["Riya", "Arjun", "Aman"];
    show(friends[0]); (a) Arjun (b) Aman (c) Riya
36. 36.💾 What number does this code show?
    let notes = ["Maths", "Hindi", "Sports", "Art"];
    notes.push("Science");
    notes.push("Music");
    show(notes.length);
37. 37.Which of these fits saving on the phone? (a) chat messages to friends (b) the sound on/off setting (c) a shared to-do list (d) photos on two devices
38. 38.💾 pop() takes off the last item. What does this code show?
    let notes = ["Hindi", "Sports", "Science"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Sports (b) Science (c) Hindi
39. 39.Which of these fits saving in the cloud? (a) notes to read offline (b) the sound on/off setting (c) a draft you are typing (d) chat messages to friends
40. 40.💾 What number does this code show?
    let notes = ["Hindi", "Sports", "Science"];
    notes.push("Maths");
    show(notes.length);

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