App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 662 · 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 = [9, 13, 13];
   let best = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] > best) {
       best = steps[i];
     }
   }
   show(best);
2. 2.🔁 What number does this code show?
   let runs = [45, 76, 21, 56, 92];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
3. 3.🔁 What number does this code show?
   let scores = [17, 1, 12, 18, 12];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
4. 4.🔁 What number does this code show?
   let steps = [9, 8, 11, 12, 6];
   let best = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] > best) {
       best = steps[i];
     }
   }
   show(best);
5. 5.🔁 What is the LAST line this code shows?
   let names = ["Zoya", "Riya", "Arjun"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Zoya (b) Hi, Riya (c) Hi, Arjun
6. 6.🔁 What number does this code show?
   let runs = [17, 15, 6];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
7. 7.🔁 Why use a loop to show 100 messages? (a) it hides them (b) it is slower (c) it uses more lines (d) less code to write
8. 8.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2 (b) 3 (c) 0, 1, 2, 3 (d) 1, 2, 3
9. 9.🔁 What number does this code show?
   let marks = [36, 17, 90];
   let count = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] >= 70) {
       count = count + 1;
     }
   }
   show(count);
10. 10.🔁 list.length tells you ___. (a) the first item (b) the last item (c) how many items it has (d) the biggest item
11. 11.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Aman", "Riya", "Kabir", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Aman (c) Hi, Riya (d) Hi, Meera
12. 12.🔁 What number does this code show?
    let steps = [14, 13, 6, 5, 3];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
13. 13.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 6 (c) 5 (d) 1
14. 14.🔁 What number does this code show?
    let marks = [18, 97, 65];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
15. 15.🔁 What number does this code show?
    let runs = [94, 85, 80, 72];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
16. 16.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Kabir", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Kabir (c) Hi, Zoya (d) Hi, Aman
17. 17.🔁 What number does this code show?
    let steps = [3, 8, 19, 17];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
18. 18.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Riya", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Arjun (c) Hi, Riya (d) Hi, Zoya
19. 19.🔁 What number does this code show?
    let scores = [13, 10, 20];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
20. 20.🔁 What number does this code show?
    let scores = [16, 17, 10, 9];
    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 runs = [17, 16, 9];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
22. 22.🔁 What number does this code show?
    let scores = [4, 3, 4, 15, 6];
    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 marks = [17, 6, 5, 8];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
24. 24.🔁 What number does this code show?
    let runs = [18, 15, 9];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
25. 25.🔁 What number does this code show?
    let steps = [2, 11, 12, 20];
    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 marks = [15, 18, 44, 73, 41];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
27. 27.🔁 What number does this code show?
    let marks = [13, 6, 17, 6, 19];
    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 scores = [22, 14, 64, 78, 75];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
29. 29.🔁 What number does this code show?
    let scores = [13, 15, 18];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
30. 30.🔁 What number does this code show?
    let steps = [16, 16, 3];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
31. 31.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Kabir", "Aman", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Zoya (c) Hi, Aman (d) Hi, Riya
32. 32.🔁 What number does this code show?
    let scores = [4, 18, 16, 12, 8];
    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, 16, 15, 2];
    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 = [74, 46, 32];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
35. 35.🔁 What number does this code show?
    let marks = [9, 11, 4, 3, 5];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
36. 36.🔁 What number does this code show?
    let runs = [11, 8, 6];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
37. 37.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Zoya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Zoya (c) Hi, Kabir (d) Hi, Meera
38. 38.🔁 What number does this code show?
    let marks = [12, 19, 20, 12, 14];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
39. 39.🔁 What number does this code show?
    let scores = [10, 98, 92, 83, 27];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
40. 40.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Meera", "Aman", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Riya (c) Hi, Kabir (d) Hi, Meera

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