App Dev Worksheet: Variables, Lists and Saving

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

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