App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 910 · 40 questions

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.

1. 1.🔁 What does a loop do? (a) deletes code (b) draws icons (c) saves photos (d) repeats code
2. 2.🔁 What number does this code show?
   let runs = [10, 6, 13];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
3. 3.🔁 What is the LAST line this code shows?
   let names = ["Arjun", "Riya", "Meera"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Arjun (b) Hi, Riya (c) Hi, Meera
4. 4.🔁 What is the LAST line this code shows?
   let names = ["Aman", "Meera", "Kabir", "Riya", "Zoya"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Kabir (b) Hi, Aman (c) Hi, Meera (d) Hi, Zoya
5. 5.🔁 What number does this code show?
   let marks = [58, 75, 10, 81];
   let count = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
6. 6.🔁 What number does this code show?
   let marks = [11, 15, 17, 12];
   let best = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] > best) {
       best = marks[i];
     }
   }
   show(best);
7. 7.🔁 What number does this code show?
   let steps = [11, 1, 4];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
8. 8.🔁 What number does this code show?
   let marks = [9, 5, 3, 3, 17];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
9. 9.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 1 (c) 5 (d) 6
10. 10.🔁 What number does this code show?
    let marks = [2, 13, 13, 12];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
11. 11.🔁 Why use a loop to show 100 messages? (a) less code to write (b) it hides them (c) it uses more lines (d) it is slower
12. 12.🔁 What number does this code show?
    let scores = [44, 32, 45];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
13. 13.🔁 What number does this code show?
    let scores = [15, 16, 1];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
14. 14.🔁 What number does this code show?
    let runs = [6, 11, 20, 1];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
15. 15.🔁 What number does this code show?
    let scores = [8, 10, 11, 8];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
16. 16.🔁 What number does this code show?
    let runs = [4, 5, 6, 3];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
17. 17.🔁 What number does this code show?
    let steps = [81, 62, 76, 58];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
18. 18.🔁 What number does this code show?
    let runs = [2, 4, 15, 11];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
19. 19.🔁 What number does this code show?
    let scores = [51, 71, 29, 37];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
20. 20.🔁 What number does this code show?
    let marks = [30, 88, 64, 64];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
21. 21.🔁 What number does this code show?
    let marks = [12, 9, 3, 3];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
22. 22.🔁 What number does this code show?
    let scores = [10, 7, 18, 17, 7];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
23. 23.🔁 What number does this code show?
    let scores = [77, 88, 19, 31];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
24. 24.🔁 What number does this code show?
    let scores = [13, 16, 10, 13, 14];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
25. 25.🔁 What number does this code show?
    let steps = [14, 14, 18];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
26. 26.🔁 list.length tells you ___. (a) the biggest item (b) the last item (c) how many items it has (d) the first item
27. 27.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Riya (c) Hi, Meera
28. 28.🔁 What number does this code show?
    let steps = [94, 60, 42];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
29. 29.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Arjun", "Kabir", "Riya", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Arjun (c) Hi, Zoya (d) Hi, Meera
30. 30.🔁 What number does this code show?
    let runs = [7, 7, 3, 11, 6];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
31. 31.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Arjun (c) Hi, Riya
32. 32.🔁 What number does this code show?
    let runs = [4, 18, 13, 12, 10];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
33. 33.🔁 What number does this code show?
    let steps = [19, 12, 3];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
34. 34.🔁 What number does this code show?
    let runs = [1, 3, 8];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
35. 35.🔁 What number does this code show?
    let scores = [19, 10, 9, 14];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
36. 36.🔁 What number does this code show?
    let runs = [1, 19, 15, 20];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
37. 37.🔁 What number does this code show?
    let scores = [4, 15, 18];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
38. 38.🔁 What number does this code show?
    let steps = [77, 92, 43];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
39. 39.🔁 What number does this code show?
    let steps = [8, 19, 3, 20];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
40. 40.🔁 What number does this code show?
    let scores = [17, 19, 13, 19, 19];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);

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