App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 78 · 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 runs = [11, 12, 3, 18, 12];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
2. 2.🔁 A loop over a list of 5 items runs its body how many times? (a) 6 (b) 1 (c) 4 (d) 5
3. 3.🔁 What number does this code show?
   let steps = [96, 43, 26, 57];
   let count = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
4. 4.🔁 What is the LAST line this code shows?
   let names = ["Aman", "Arjun", "Kabir", "Meera"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Arjun (b) Hi, Aman (c) Hi, Meera (d) Hi, Kabir
5. 5.🔁 What is the LAST line this code shows?
   let names = ["Arjun", "Kabir", "Meera", "Riya"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Arjun (b) Hi, Meera (c) Hi, Kabir (d) Hi, Riya
6. 6.🔁 What number does this code show?
   let scores = [8, 18, 17];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
7. 7.🔁 What number does this code show?
   let scores = [7, 10, 7, 6];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
8. 8.🔁 What number does this code show?
   let scores = [11, 5, 20, 2];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
9. 9.🔁 What is the LAST line this code shows?
   let names = ["Meera", "Zoya", "Aman", "Kabir", "Arjun"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Aman (b) Hi, Meera (c) Hi, Zoya (d) Hi, Arjun
10. 10.🔁 What number does this code show?
    let steps = [32, 72, 23, 98, 31];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
11. 11.🔁 What number does this code show?
    let scores = [30, 88, 59, 36];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
12. 12.🔁 What number does this code show?
    let scores = [3, 5, 20];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
13. 13.🔁 What number does this code show?
    let steps = [7, 7, 17, 14];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
14. 14.🔁 What number does this code show?
    let steps = [65, 97, 84];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
15. 15.🔁 What number does this code show?
    let marks = [54, 98, 38];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
16. 16.🔁 list.length tells you ___. (a) how many items it has (b) the first item (c) the last item (d) the biggest item
17. 17.🔁 What number does this code show?
    let runs = [42, 14, 83, 56, 84];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
18. 18.🔁 What number does this code show?
    let scores = [15, 15, 6, 4, 2];
    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 = [3, 9, 14];
    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 scores = [4, 15, 14, 9, 12];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
21. 21.🔁 What number does this code show?
    let scores = [6, 10, 5, 20, 12];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
22. 22.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Riya", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Arjun (c) Hi, Aman (d) Hi, Riya
23. 23.🔁 What number does this code show?
    let steps = [51, 94, 89];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
24. 24.🔁 What number does this code show?
    let scores = [10, 5, 3, 5];
    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 = [15, 13, 18];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
26. 26.🔁 What number does this code show?
    let scores = [5, 19, 14, 15, 6];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
27. 27.🔁 Why use a loop to show 100 messages? (a) it hides them (b) less code to write (c) it is slower (d) it uses more lines
28. 28.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2, 3 (b) 3 (c) 0, 1, 2 (d) 1, 2, 3
29. 29.🔁 What does a loop do? (a) draws icons (b) saves photos (c) repeats code (d) deletes code
30. 30.🔁 What number does this code show?
    let steps = [3, 7, 3, 15];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
31. 31.🔁 What number does this code show?
    let runs = [17, 12, 16];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
32. 32.🔁 What number does this code show?
    let marks = [7, 2, 9, 10, 10];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
33. 33.🔁 What number does this code show?
    let runs = [20, 3, 6, 16];
    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 marks = [17, 12, 3];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
35. 35.🔁 What number does this code show?
    let runs = [11, 8, 1];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
36. 36.🔁 What number does this code show?
    let scores = [20, 16, 15, 2, 15];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
37. 37.🔁 What number does this code show?
    let runs = [4, 16, 6];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
38. 38.🔁 What number does this code show?
    let steps = [62, 61, 53, 54];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
39. 39.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Meera", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Kabir (c) Hi, Aman
40. 40.🔁 What number does this code show?
    let scores = [19, 41, 11, 64, 83];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);

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