← Loops over lists lesson New set →

App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 46 · 40 questions
TalentJR

Developer's tip (One by one): for (let i = 0; i < list.length; i++) visits every item, from position 0. Total: add each item. Count: add 1 when the test is true. Best: keep the biggest so far. The body runs once per item: a list of 5 runs it 5 times.

NameDateTime takenScore ___ / 40
  1. 1.🔁 What does a loop do? (a) saves photos (b) draws icons (c) repeats code (d) deletes code
  2. 2.🔁 What number does this code show?
    let marks = [5, 20, 2, 2];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  3. 3.🔁 What number does this code show?
    let marks = [1, 16, 8];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  4. 4.🔁 What number does this code show?
    let runs = [14, 76, 43];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  5. 5.🔁 What number does this code show?
    let steps = [19, 18, 19];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  6. 6.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Zoya", "Riya", "Aman", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Riya (c) Hi, Kabir (d) Hi, Meera
  7. 7.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Arjun (c) Hi, Zoya
  8. 8.🔁 What number does this code show?
    let steps = [13, 13, 13, 20, 15];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  9. 9.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 6 (c) 5 (d) 1
  10. 10.🔁 What number does this code show?
    let scores = [15, 20, 17, 2, 10];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  11. 11.🔁 list.length tells you ___. (a) the biggest item (b) the last item (c) the first item (d) how many items it has
  12. 12.🔁 Why use a loop to show 100 messages? (a) it hides them (b) it uses more lines (c) it is slower (d) less code to write
  13. 13.🔁 What number does this code show?
    let steps = [11, 12, 3];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  14. 14.🔁 What number does this code show?
    let marks = [11, 8, 1];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  15. 15.🔁 What number does this code show?
    let scores = [31, 15, 21, 99, 64];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  16. 16.🔁 What number does this code show?
    let marks = [93, 30, 25, 89];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  17. 17.🔁 What number does this code show?
    let marks = [5, 9, 2, 10, 10];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  18. 18.🔁 What number does this code show?
    let scores = [16, 10, 15, 10];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  19. 19.🔁 What number does this code show?
    let steps = [1, 15, 5, 10, 9];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  20. 20.🔁 What number does this code show?
    let steps = [5, 15, 17, 11];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  21. 21.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Aman", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Aman (c) Hi, Meera (d) Hi, Arjun
  22. 22.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Riya", "Meera", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Zoya (c) Hi, Aman (d) Hi, Riya
  23. 23.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2 (b) 1, 2, 3 (c) 0, 1, 2, 3 (d) 3
  24. 24.🔁 What number does this code show?
    let scores = [15, 8, 5, 9, 18];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  25. 25.🔁 What number does this code show?
    let scores = [17, 7, 4, 16, 5];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  26. 26.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Meera", "Riya", "Aman", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Riya (b) Hi, Zoya (c) Hi, Meera (d) Hi, Kabir
  27. 27.🔁 What number does this code show?
    let scores = [67, 32, 75, 56];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  28. 28.🔁 What number does this code show?
    let steps = [18, 18, 3];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  29. 29.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Arjun", "Aman", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Aman (d) Hi, Meera
  30. 30.🔁 What number does this code show?
    let marks = [24, 14, 15, 95];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  31. 31.🔁 What number does this code show?
    let scores = [19, 18, 7];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
  32. 32.🔁 What number does this code show?
    let runs = [19, 35, 87, 64, 97];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  33. 33.🔁 What number does this code show?
    let marks = [9, 13, 1];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  34. 34.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Zoya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Kabir (b) Hi, Arjun (c) Hi, Zoya
  35. 35.🔁 What number does this code show?
    let runs = [51, 71, 19, 37, 55];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  36. 36.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Meera", "Riya", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Meera (b) Hi, Riya (c) Hi, Kabir (d) Hi, Aman
  37. 37.🔁 What number does this code show?
    let marks = [6, 18, 11, 12, 19];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  38. 38.🔁 What number does this code show?
    let marks = [28, 93, 17];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  39. 39.🔁 What number does this code show?
    let scores = [14, 16, 20, 4, 10];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  40. 40.🔁 What number does this code show?
    let scores = [3, 18, 11];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);

Answer key

  1. repeats code
  2. 29
  3. 25
  4. 1
  5. 56
  6. Hi, Meera
  7. Hi, Zoya
  8. 20
  9. 5
  10. 64
  11. how many items it has
  12. less code to write
  13. 26
  14. 11
  15. 2
  16. 2
  17. 36
  18. 51
  19. 15
  20. 48
  21. Hi, Zoya
  22. Hi, Zoya
  23. 0, 1, 2
  24. 55
  25. 49
  26. Hi, Kabir
  27. 3
  28. 39
  29. Hi, Meera
  30. 1
  31. 19
  32. 2
  33. 23
  34. Hi, Kabir
  35. 3
  36. Hi, Aman
  37. 19
  38. 1
  39. 64
  40. 32

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