← Loops over lists lesson New set →

App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 696 · 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 is the LAST line this code shows?
    let names = ["Zoya", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Kabir
  2. 2.🔁 Why use a loop to show 100 messages? (a) less code to write (b) it uses more lines (c) it is slower (d) it hides them
  3. 3.🔁 What number does this code show?
    let scores = [19, 11, 6];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  4. 4.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2, 3 (b) 1, 2, 3 (c) 0, 1, 2 (d) 3
  5. 5.🔁 A loop over a list of 5 items runs its body how many times? (a) 6 (b) 5 (c) 1 (d) 4
  6. 6.🔁 What number does this code show?
    let scores = [95, 71, 12, 93];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  7. 7.🔁 What number does this code show?
    let scores = [22, 12, 46, 85];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  8. 8.🔁 What number does this code show?
    let steps = [9, 14, 4, 11];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  9. 9.🔁 What number does this code show?
    let runs = [16, 8, 1];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  10. 10.🔁 What number does this code show?
    let scores = [98, 95, 71, 58];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
  11. 11.🔁 What number does this code show?
    let scores = [86, 23, 50];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  12. 12.🔁 What number does this code show?
    let marks = [30, 78, 25];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  13. 13.🔁 What number does this code show?
    let runs = [10, 2, 20];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  14. 14.🔁 What number does this code show?
    let marks = [87, 73, 84];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  15. 15.🔁 What number does this code show?
    let steps = [2, 9, 9];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  16. 16.🔁 What number does this code show?
    let scores = [13, 16, 20];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  17. 17.🔁 What number does this code show?
    let scores = [39, 77, 89];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  18. 18.🔁 What does a loop do? (a) deletes code (b) draws icons (c) repeats code (d) saves photos
  19. 19.🔁 What number does this code show?
    let scores = [83, 68, 50, 13];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
  20. 20.🔁 What number does this code show?
    let scores = [89, 42, 95, 67];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  21. 21.🔁 What number does this code show?
    let scores = [6, 13, 6, 11, 19];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
  22. 22.🔁 What number does this code show?
    let steps = [10, 3, 11, 19];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
  23. 23.🔁 What number does this code show?
    let runs = [4, 16, 20, 5, 15];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  24. 24.🔁 What number does this code show?
    let runs = [51, 27, 62, 18, 94];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  25. 25.🔁 What number does this code show?
    let runs = [14, 11, 8];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  26. 26.🔁 What number does this code show?
    let steps = [7, 20, 2];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  27. 27.🔁 What number does this code show?
    let marks = [1, 18, 7, 16, 14];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
  28. 28.🔁 What number does this code show?
    let steps = [74, 66, 22, 13, 48];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
  29. 29.🔁 What number does this code show?
    let scores = [16, 88, 68];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
  30. 30.🔁 What number does this code show?
    let runs = [11, 7, 20];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  31. 31.🔁 What number does this code show?
    let runs = [4, 19, 12, 1, 13];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  32. 32.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Aman
  33. 33.🔁 What number does this code show?
    let marks = [4, 17, 20, 19, 11];
    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", "Kabir", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    }     (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Kabir
  35. 35.🔁 What number does this code show?
    let runs = [11, 20, 6, 20];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
  36. 36.🔁 What number does this code show?
    let runs = [2, 17, 17];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
  37. 37.🔁 What number does this code show?
    let marks = [10, 19, 20];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  38. 38.🔁 What number does this code show?
    let marks = [11, 15, 13, 5, 19];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
  39. 39.🔁 What number does this code show?
    let steps = [7, 12, 18, 12, 3];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
  40. 40.🔁 What number does this code show?
    let steps = [1, 6, 7, 14];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);

Answer key

  1. Hi, Kabir
  2. less code to write
  3. 36
  4. 0, 1, 2
  5. 5
  6. 3
  7. 1
  8. 38
  9. 16
  10. 3
  11. 2
  12. 1
  13. 20
  14. 3
  15. 20
  16. 49
  17. 2
  18. repeats code
  19. 2
  20. 4
  21. 55
  22. 19
  23. 20
  24. 3
  25. 33
  26. 29
  27. 18
  28. 2
  29. 2
  30. 38
  31. 49
  32. Hi, Aman
  33. 71
  34. Hi, Zoya
  35. 57
  36. 17
  37. 49
  38. 63
  39. 52
  40. 28

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