App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 218 · 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 scores = [8, 11, 11, 2];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
2. 2.🔁 What number does this code show?
   let steps = [21, 14, 73];
   let count = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
3. 3.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2 (b) 3 (c) 1, 2, 3 (d) 0, 1, 2, 3
4. 4.🔁 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, Aman (c) Hi, Kabir
5. 5.🔁 What number does this code show?
   let scores = [1, 20, 13, 17, 10];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
6. 6.🔁 What number does this code show?
   let scores = [12, 19, 19];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
7. 7.🔁 What number does this code show?
   let scores = [25, 96, 57, 31, 42];
   let count = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
8. 8.🔁 What is the LAST line this code shows?
   let names = ["Aman", "Zoya", "Arjun"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Zoya (b) Hi, Aman (c) Hi, Arjun
9. 9.🔁 What number does this code show?
   let runs = [14, 17, 14];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
10. 10.🔁 What number does this code show?
    let scores = [19, 20, 2];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
11. 11.🔁 What number does this code show?
    let scores = [14, 4, 15, 10, 7];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
12. 12.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Meera (d) Hi, Riya
13. 13.🔁 What number does this code show?
    let marks = [92, 84, 52];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
14. 14.🔁 What number does this code show?
    let steps = [43, 84, 17, 79, 32];
    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 = [4, 8, 2, 14];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
16. 16.🔁 list.length tells you ___. (a) the last item (b) how many items it has (c) the biggest item (d) the first item
17. 17.🔁 What number does this code show?
    let steps = [17, 3, 4, 1, 13];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
18. 18.🔁 What number does this code show?
    let steps = [4, 12, 11];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
19. 19.🔁 What number does this code show?
    let scores = [98, 70, 34, 36];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
20. 20.🔁 What number does this code show?
    let marks = [20, 19, 11];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
21. 21.🔁 What number does this code show?
    let runs = [6, 5, 16, 16];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
22. 22.🔁 What number does this code show?
    let runs = [9, 12, 8];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
23. 23.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Meera", "Arjun", "Aman", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Meera (d) Hi, Riya
24. 24.🔁 What number does this code show?
    let runs = [16, 18, 18, 2];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
25. 25.🔁 What number does this code show?
    let marks = [19, 2, 6, 1, 13];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
26. 26.🔁 What number does this code show?
    let scores = [52, 43, 14, 67];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
27. 27.🔁 What number does this code show?
    let marks = [27, 31, 86, 18];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
28. 28.🔁 What number does this code show?
    let scores = [16, 9, 2, 2];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
29. 29.🔁 Why use a loop to show 100 messages? (a) it is slower (b) it uses more lines (c) less code to write (d) it hides them
30. 30.🔁 What number does this code show?
    let scores = [10, 4, 14];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
31. 31.🔁 What number does this code show?
    let steps = [6, 11, 20, 9];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
32. 32.🔁 What number does this code show?
    let steps = [17, 6, 5, 17, 6];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
33. 33.🔁 What number does this code show?
    let runs = [17, 20, 17];
    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 = [35, 53, 45];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
35. 35.🔁 What number does this code show?
    let marks = [13, 19, 13, 20, 8];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
36. 36.🔁 What number does this code show?
    let runs = [9, 18, 16];
    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 steps = [11, 14, 7, 9, 15];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
38. 38.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 5 (c) 6 (d) 1
39. 39.🔁 What number does this code show?
    let scores = [11, 7, 6];
    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 steps = [40, 21, 28, 73, 36];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);

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