App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 224 · 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 stars = 7;
   stars = stars - 7;
   stars = stars + 1;
   show(stars);
2. 2.💾 What number does this code show?
   let friends = ["Aman", "Arjun", "Kabir", "Riya"];
   friends.push("Zoya");
   show(friends.length);
3. 3.💾 What number does this code show?
   let friends = ["Zoya", "Kabir", "Riya", "Arjun"];
   friends.push("Aman");
   friends.push("Meera");
   show(friends.length);
4. 4.True or false: a shared to-do list fits saving on the phone. (a) False (b) True
5. 5.💾 What does this code show? (Positions start at 0.)
   let songs = ["Stars", "Rain", "Ocean", "Sunrise"];
   show(songs[1]); (a) Stars (b) Sunrise (c) Rain (d) Ocean
6. 6.💾 pop() takes off the last item. What does this code show?
   let songs = ["Rain", "Kites", "Stars"];
   songs.pop();
   show(songs[songs.length - 1]); (a) Kites (b) Stars (c) Rain
7. 7.💾 What does this code show? (Positions start at 0.)
   let notes = ["Maths", "Hindi", "Art", "Sports"];
   show(notes[0]); (a) Maths (b) Sports (c) Art (d) Hindi
8. 8.💾 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
9. 9.💾 What number does this code show?
   let stars = 8;
   stars = stars - 1;
   stars = stars + 1;
   show(stars);
10. 10.True or false: the sound on/off setting fits saving on the phone. (a) False (b) True
11. 11.💾 Where should the app save photos on two devices: on the phone or in the cloud? (a) on the phone (b) in the cloud
12. 12.💾 What is a variable? (a) a picture (b) a named box for a value (c) a type of screen (d) a phone setting
13. 13.💾 pop() takes off the last item. What does this code show?
    let songs = ["Stars", "Sunrise", "Kites"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Sunrise (b) Stars (c) Kites
14. 14.Which of these fits saving on the phone? (a) a class leaderboard (b) a shared to-do list (c) notes to read offline (d) chat messages to friends
15. 15.💾 What number does this code show?
    let coins = 6;
    coins = coins - 4;
    coins = coins + 4;
    show(coins);
16. 16.💾 What does this code show? (Positions start at 0.)
    let friends = ["Arjun", "Meera", "Kabir", "Zoya", "Aman"];
    show(friends[1]); (a) Kabir (b) Zoya (c) Meera (d) Arjun
17. 17.True or false: photos on two devices fits saving on the phone. (a) True (b) False
18. 18.💾 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
19. 19.💾 What does this code show? (Positions start at 0.)
    let friends = ["Riya", "Aman", "Zoya", "Arjun", "Kabir"];
    show(friends[4]); (a) Zoya (b) Riya (c) Kabir (d) Aman
20. 20.💾 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
21. 21.Which of these fits saving in the cloud? (a) your last game level (b) notes to read offline (c) a class leaderboard (d) the sound on/off setting
22. 22.💾 What number does this code show?
    let notes = ["Maths", "Sports"];
    notes.push("Music");
    show(notes.length);
23. 23.True or false: your last game level fits saving in the cloud. (a) True (b) False
24. 24.💾 What number does this code show?
    let lives = 4;
    lives = lives - 2;
    lives = lives + 3;
    show(lives);
25. 25.💾 Which can hold many values in order? (a) a switch (b) a list (c) a single number (d) a button
26. 26.💾 pop() takes off the last item. What does this code show?
    let songs = ["Ocean", "Kites", "Monsoon"];
    songs.pop();
    show(songs[songs.length - 1]); (a) Kites (b) Monsoon (c) Ocean
27. 27.True or false: the sound on/off setting fits saving in the cloud. (a) False (b) True
28. 28.💾 What does this code show? (Positions start at 0.)
    let songs = ["Ocean", "Sunrise", "Monsoon", "Rain", "Stars"];
    show(songs[1]); (a) Monsoon (b) Rain (c) Sunrise (d) Ocean
29. 29.💾 What number does this code show?
    let score = 5;
    score = score - 3;
    score = score + 2;
    show(score);
30. 30.💾 What does this code show? (Positions start at 0.)
    let friends = ["Riya", "Meera", "Aman", "Arjun"];
    show(friends[1]); (a) Riya (b) Meera (c) Aman (d) Arjun
31. 31.Which of these fits saving on the phone? (a) a shared to-do list (b) photos on two devices (c) your last game level (d) chat messages to friends
32. 32.💾 What number does this code show?
    let friends = ["Meera", "Kabir", "Riya"];
    friends.push("Aman");
    friends.push("Arjun");
    show(friends.length);
33. 33.💾 What does this code show? (Positions start at 0.)
    let songs = ["Sunrise", "Stars", "Monsoon", "Ocean", "Rain"];
    show(songs[2]); (a) Stars (b) Sunrise (c) Monsoon (d) Ocean
34. 34.💾 What number does this code show?
    let notes = ["Sports", "Maths"];
    notes.push("Music");
    show(notes.length);
35. 35.💾 In most code, the first item of a list is at position ___. (a) 0 (b) 2 (c) 1 (d) 10
36. 36.Which of these fits saving on the phone? (a) a draft you are typing (b) a shared to-do list (c) chat messages to friends (d) photos on two devices
37. 37.💾 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
38. 38.💾 Data saved only on the phone is lost when ___. (a) the screen turns off (b) you send a message (c) the app is closed (d) the phone is lost
39. 39.💾 What does this code show? (Positions start at 0.)
    let notes = ["Art", "Sports", "Hindi", "Music", "Science"];
    show(notes[0]); (a) Hindi (b) Art (c) Sports (d) Music
40. 40.Which of these fits saving on the phone? (a) chat messages to friends (b) photos on two devices (c) a shared to-do list (d) the sound on/off setting

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