App Dev Worksheet: Variables, Lists and Saving

App development lesson 15: Data: variables, lists and saving · Set 361 · 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 = 9;
   coins = coins - 8;
   coins = coins + 3;
   show(coins);
2. 2.True or false: a shared to-do list fits saving in the cloud. (a) True (b) False
3. 3.True or false: a draft you are typing fits saving in the cloud. (a) False (b) True
4. 4.💾 What number does this code show?
   let stars = 3;
   stars = stars - 2;
   stars = stars + 3;
   show(stars);
5. 5.True or false: notes to read offline fits saving on the phone. (a) False (b) True
6. 6.💾 What does this code show? (Positions start at 0.)
   let friends = ["Aman", "Kabir", "Zoya"];
   show(friends[0]); (a) Zoya (b) Aman (c) Kabir
7. 7.💾 Data saved only on the phone is lost when ___. (a) the phone is lost (b) the screen turns off (c) the app is closed (d) you send a message
8. 8.💾 pop() takes off the last item. What does this code show?
   let notes = ["Maths", "Art", "Hindi", "Science"];
   notes.pop();
   show(notes[notes.length - 1]); (a) Science (b) Maths (c) Art (d) Hindi
9. 9.Which of these fits saving on the phone? (a) a class leaderboard (b) the sound on/off setting (c) a shared to-do list (d) chat messages to friends
10. 10.💾 Saving data in the cloud lets you ___. (a) use it on any device (b) shrink the app (c) never need a password (d) skip the internet
11. 11.Which of these fits saving in the cloud? (a) notes to read offline (b) chat messages to friends (c) your last game level (d) a draft you are typing
12. 12.💾 What number does this code show?
    let notes = ["Maths", "Sports", "Art"];
    notes.push("Music");
    notes.push("Science");
    show(notes.length);
13. 13.💾 What is a variable? (a) a picture (b) a phone setting (c) a type of screen (d) a named box for a value
14. 14.💾 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
15. 15.💾 What number does this code show?
    let stars = 4;
    stars = stars - 2;
    stars = stars + 1;
    show(stars);
16. 16.True or false: photos on two devices fits saving on the phone. (a) True (b) False
17. 17.💾 What number does this code show?
    let friends = ["Riya", "Aman", "Meera", "Kabir"];
    friends.push("Arjun");
    friends.push("Zoya");
    show(friends.length);
18. 18.💾 In most code, the first item of a list is at position ___. (a) 0 (b) 1 (c) 2 (d) 10
19. 19.💾 pop() takes off the last item. What does this code show?
    let notes = ["Music", "Science", "Sports", "Maths"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Science (b) Music (c) Maths (d) Sports
20. 20.💾 pop() takes off the last item. What does this code show?
    let notes = ["Maths", "Hindi", "Music", "Sports", "Science"];
    notes.pop();
    show(notes[notes.length - 1]); (a) Maths (b) Music (c) Hindi (d) Sports
21. 21.💾 Where should the app save your last game level: on the phone or in the cloud? (a) on the phone (b) in the cloud
22. 22.True or false: the sound on/off setting fits saving in the cloud. (a) False (b) True
23. 23.True or false: your last game level fits saving on the phone. (a) True (b) False
24. 24.Which of these fits saving on the phone? (a) a shared to-do list (b) chat messages to friends (c) a class leaderboard (d) a draft you are typing
25. 25.True or false: a shared to-do list fits saving on the phone. (a) False (b) True
26. 26.True or false: photos on two devices fits saving in the cloud. (a) False (b) True
27. 27.💾 Where should the app save notes to read offline: on the phone or in the cloud? (a) on the phone (b) in the cloud
28. 28.💾 Where should the app save chat messages to friends: on the phone or in the cloud? (a) in the cloud (b) on the phone
29. 29.💾 What number does this code show?
    let stars = 5;
    stars = stars - 1;
    stars = stars + 3;
    show(stars);
30. 30.💾 Which can hold many values in order? (a) a switch (b) a button (c) a single number (d) a list
31. 31.True or false: chat messages to friends fits saving on the phone. (a) True (b) False
32. 32.Which of these fits saving on the phone? (a) photos on two devices (b) chat messages to friends (c) a class leaderboard (d) notes to read offline
33. 33.💾 What number does this code show?
    let coins = 8;
    coins = coins - 6;
    coins = coins + 1;
    show(coins);
34. 34.💾 What number does this code show?
    let friends = ["Riya", "Kabir", "Meera"];
    friends.push("Zoya");
    friends.push("Aman");
    show(friends.length);
35. 35.True or false: your last game level fits saving in the cloud. (a) True (b) False
36. 36.💾 What number does this code show?
    let friends = ["Kabir", "Riya", "Zoya", "Meera"];
    friends.push("Arjun");
    friends.push("Aman");
    show(friends.length);
37. 37.💾 pop() takes off the last item. What does this code show?
    let friends = ["Kabir", "Riya", "Meera", "Arjun"];
    friends.pop();
    show(friends[friends.length - 1]); (a) Riya (b) Meera (c) Arjun (d) Kabir
38. 38.Which of these fits saving in the cloud? (a) a draft you are typing (b) a class leaderboard (c) notes to read offline (d) your last game level
39. 39.💾 What number does this code show?
    let friends = ["Arjun", "Riya", "Kabir", "Aman"];
    friends.push("Meera");
    friends.push("Zoya");
    show(friends.length);
40. 40.💾 What number does this code show?
    let score = 8;
    score = score - 3;
    score = score + 3;
    show(score);

Free app development lessons, practice and worksheets at talentjr.in/app-development-for-students