App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 750 · 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 number does this code show?
   let steps = [1, 5, 3];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
2. 2.🔁 What number does this code show?
   let scores = [10, 19, 3];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
3. 3.🔁 What number does this code show?
   let scores = [20, 11, 12, 7];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
4. 4.🔁 A loop over a list of 5 items runs its body how many times? (a) 1 (b) 5 (c) 4 (d) 6
5. 5.🔁 What number does this code show?
   let runs = [80, 87, 84, 69];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
6. 6.🔁 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
7. 7.🔁 What is the LAST line this code shows?
   let names = ["Riya", "Zoya", "Aman", "Meera"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Aman (b) Hi, Riya (c) Hi, Meera (d) Hi, Zoya
8. 8.🔁 What number does this code show?
   let steps = [18, 10, 97, 90];
   let count = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
9. 9.🔁 What does a loop do? (a) deletes code (b) draws icons (c) saves photos (d) repeats code
10. 10.🔁 What number does this code show?
    let marks = [17, 1, 9, 12, 20];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
11. 11.🔁 What number does this code show?
    let scores = [7, 4, 10, 15];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
12. 12.🔁 list.length tells you ___. (a) how many items it has (b) the biggest item (c) the first item (d) the last item
13. 13.🔁 What number does this code show?
    let scores = [14, 7, 18, 11, 2];
    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 steps = [20, 11, 19];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
15. 15.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 3 (b) 0, 1, 2 (c) 0, 1, 2, 3 (d) 1, 2, 3
16. 16.🔁 What number does this code show?
    let runs = [16, 7, 4, 10];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
17. 17.🔁 What number does this code show?
    let marks = [4, 8, 1];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
18. 18.🔁 What number does this code show?
    let scores = [15, 4, 20, 19];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
19. 19.🔁 What number does this code show?
    let runs = [8, 10, 6];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
20. 20.🔁 What number does this code show?
    let steps = [20, 8, 15, 1, 14];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
21. 21.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Meera (c) Hi, Aman
22. 22.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Kabir", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Arjun (c) Hi, Meera
23. 23.🔁 What number does this code show?
    let runs = [1, 7, 10];
    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 steps = [34, 38, 89, 54];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
25. 25.🔁 What number does this code show?
    let scores = [38, 33, 46, 98, 20];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
26. 26.🔁 What number does this code show?
    let scores = [6, 3, 6, 18, 14];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
27. 27.🔁 What number does this code show?
    let runs = [6, 15, 15, 14, 7];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
28. 28.🔁 What number does this code show?
    let runs = [7, 6, 10, 11, 4];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
29. 29.🔁 What number does this code show?
    let steps = [34, 19, 20, 26, 26];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
30. 30.🔁 What number does this code show?
    let marks = [24, 29, 19, 24];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
31. 31.🔁 What number does this code show?
    let scores = [16, 11, 14, 9, 2];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
32. 32.🔁 What number does this code show?
    let scores = [20, 10, 7, 6, 2];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
33. 33.🔁 What number does this code show?
    let runs = [4, 18, 7, 9];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
34. 34.🔁 What number does this code show?
    let runs = [16, 20, 6, 19, 2];
    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 steps = [4, 1, 4];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
36. 36.🔁 What number does this code show?
    let steps = [73, 84, 55, 45];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
37. 37.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Kabir (c) Hi, Aman
38. 38.🔁 What number does this code show?
    let steps = [32, 32, 20];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
39. 39.🔁 What number does this code show?
    let steps = [7, 5, 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 marks = [65, 54, 65];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);

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