App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 411 · 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 = 3;
   points = points - 2;
   points = points + 1;
   show(points);
2. 2.💾 What number does this code show?
   let friends = ["Riya", "Arjun", "Kabir"];
   friends.push("Meera");
   friends.push("Zoya");
   show(friends.length);
3. 3.💾 What does this code show? (Positions start at 0.)
   let notes = ["Science", "Sports", "Art", "Hindi"];
   show(notes[0]); (a) Hindi (b) Sports (c) Art (d) Science
4. 4.💾 What does this code show? (Positions start at 0.)
   let friends = ["Zoya", "Kabir", "Arjun"];
   show(friends[1]); (a) Arjun (b) Kabir (c) Zoya
5. 5.True or false: the sound on/off setting fits saving in the cloud. (a) False (b) True
6. 6.Which of these fits saving in the cloud? (a) your last game level (b) a shared to-do list (c) the sound on/off setting (d) a draft you are typing
7. 7.Which of these fits saving on the phone? (a) chat messages to friends (b) a draft you are typing (c) a class leaderboard (d) photos on two devices
8. 8.Which of these fits saving in the cloud? (a) a draft you are typing (b) your last game level (c) the sound on/off setting (d) a class leaderboard
9. 9.True or false: a shared to-do list fits saving in the cloud. (a) True (b) False
10. 10.💾 Where should the app save photos on two devices: on the phone or in the cloud? (a) in the cloud (b) on the phone
11. 11.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
12. 12.💾 pop() takes off the last item. What does this code show?
    let notes = ["Sports", "Maths", "Science", "Hindi", "Music"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Sports (b) Science (c) Maths (d) Hindi
13. 13.Which of these fits saving in the cloud? (a) a draft you are typing (b) notes to read offline (c) your last game level (d) chat messages to friends
14. 14.💾 pop() takes off the last item. What does this code show?
    let songs = ["Rain", "Sunrise", "Monsoon"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Rain (b) Sunrise (c) Monsoon
15. 15.💾 Where should the app save notes to read offline: on the phone or in the cloud? (a) in the cloud (b) on the phone
16. 16.💾 Data saved only on the phone is lost when ___. (a) the phone is lost (b) the screen turns off (c) you send a message (d) the app is closed
17. 17.💾 What is a variable? (a) a type of screen (b) a phone setting (c) a picture (d) a named box for a value
18. 18.💾 What number does this code show?
    let lives = 6;
    lives = lives - 6;
    lives = lives + 3;
    show(lives);
19. 19.💾 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
20. 20.True or false: a draft you are typing fits saving in the cloud. (a) False (b) True
21. 21.💾 What does this code show? (Positions start at 0.)
    let friends = ["Meera", "Arjun", "Riya"];
    show(friends[1]); (a) Riya (b) Arjun (c) Meera
22. 22.💾 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
23. 23.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) in the cloud (b) on the phone
24. 24.💾 Which works with no internet at all? (a) data saved on the phone (b) a cloud leaderboard (c) a cloud backup (d) a shared chat
25. 25.Which of these fits saving on the phone? (a) chat messages to friends (b) notes to read offline (c) a shared to-do list (d) photos on two devices
26. 26.💾 In most code, the first item of a list is at position ___. (a) 2 (b) 1 (c) 0 (d) 10
27. 27.True or false: notes to read offline fits saving on the phone. (a) True (b) False
28. 28.💾 What number does this code show?
    let notes = ["Music", "Maths"];
    notes.push("Science");
    notes.push("Art");
    show(notes.length);
29. 29.True or false: photos on two devices fits saving on the phone. (a) True (b) False
30. 30.💾 Where should the app save your last game level: on the phone or in the cloud? (a) in the cloud (b) on the phone
31. 31.💾 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
32. 32.💾 pop() takes off the last item. What does this code show?
    let friends = ["Arjun", "Zoya", "Riya", "Kabir"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Riya (b) Zoya (c) Kabir (d) Arjun
33. 33.💾 What does this code show? (Positions start at 0.)
    let notes = ["Art", "Hindi", "Maths"];
    show(notes[0]); (a) Hindi (b) Art (c) Maths
34. 34.💾 What number does this code show?
    let score = 8;
    score = score - 6;
    score = score + 2;
    show(score);
35. 35.True or false: chat messages to friends fits saving on the phone. (a) True (b) False
36. 36.💾 Which can hold many values in order? (a) a switch (b) a button (c) a list (d) a single number
37. 37.Which of these fits saving on the phone? (a) your last game level (b) photos on two devices (c) a class leaderboard (d) chat messages to friends
38. 38.💾 What number does this code show?
    let coins = 5;
    coins = coins - 1;
    coins = coins + 1;
    show(coins);
39. 39.💾 What does this code show? (Positions start at 0.)
    let friends = ["Meera", "Aman", "Kabir", "Riya"];
    show(friends[3]); (a) Kabir (b) Riya (c) Aman (d) Meera
40. 40.💾 What number does this code show?
    let songs = ["Rain", "Kites"];
    songs.push("Sunrise");
    songs.push("Ocean");
    show(songs.length);

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