App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 651 · 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 = [14, 20, 3, 18, 5];
   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 = [8, 3, 4, 3, 18];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
3. 3.🔁 What is the LAST line this code shows?
   let names = ["Arjun", "Aman", "Kabir"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Aman
4. 4.🔁 What does a loop do? (a) repeats code (b) deletes code (c) saves photos (d) draws icons
5. 5.🔁 What number does this code show?
   let steps = [5, 2, 3];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
6. 6.🔁 What number does this code show?
   let marks = [13, 15, 6, 5, 6];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
7. 7.🔁 What number does this code show?
   let scores = [2, 3, 15, 1, 10];
   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 runs = [4, 20, 5];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
9. 9.🔁 What number does this code show?
   let steps = [77, 47, 68, 66];
   let count = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] >= 40) {
       count = count + 1;
     }
   }
   show(count);
10. 10.🔁 What number does this code show?
    let marks = [85, 93, 81];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
11. 11.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 1, 2, 3 (b) 0, 1, 2 (c) 0, 1, 2, 3 (d) 3
12. 12.🔁 A loop over a list of 5 items runs its body how many times? (a) 1 (b) 4 (c) 5 (d) 6
13. 13.🔁 What number does this code show?
    let steps = [4, 5, 20, 10, 9];
    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 = [16, 13, 19, 5, 14];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
15. 15.🔁 What number does this code show?
    let runs = [13, 11, 10];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
16. 16.🔁 What number does this code show?
    let scores = [60, 53, 33, 75, 21];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
17. 17.🔁 What number does this code show?
    let steps = [20, 8, 5, 20];
    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 = ["Arjun", "Kabir", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Arjun (c) Hi, Riya
19. 19.🔁 list.length tells you ___. (a) the biggest item (b) the first item (c) the last item (d) how many items it has
20. 20.🔁 What number does this code show?
    let runs = [80, 86, 13, 35];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
21. 21.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Arjun", "Aman", "Zoya", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Meera (c) Hi, Aman (d) Hi, Arjun
22. 22.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Zoya (c) Hi, Riya (d) Hi, Meera
23. 23.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Riya", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Meera (c) Hi, Zoya
24. 24.🔁 What number does this code show?
    let scores = [18, 94, 25, 95];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
25. 25.🔁 What number does this code show?
    let scores = [13, 8, 18, 9];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
26. 26.🔁 What number does this code show?
    let steps = [17, 13, 2, 3];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
27. 27.🔁 What number does this code show?
    let runs = [7, 3, 5, 2];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
28. 28.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Zoya
29. 29.🔁 What number does this code show?
    let marks = [8, 9, 6, 14];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
30. 30.🔁 What number does this code show?
    let marks = [26, 58, 32];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
31. 31.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Arjun", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Meera (c) Hi, Riya (d) Hi, Arjun
32. 32.🔁 Why use a loop to show 100 messages? (a) it is slower (b) less code to write (c) it uses more lines (d) it hides them
33. 33.🔁 What number does this code show?
    let marks = [4, 8, 10];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
34. 34.🔁 What number does this code show?
    let scores = [14, 3, 19, 10];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
35. 35.🔁 What number does this code show?
    let scores = [11, 28, 41];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
36. 36.🔁 What number does this code show?
    let scores = [9, 6, 1, 8];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
37. 37.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Riya", "Kabir", "Meera", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Riya (c) Hi, Aman (d) Hi, Kabir
38. 38.🔁 What number does this code show?
    let runs = [53, 97, 12, 31, 81];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
39. 39.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Meera (c) Hi, Aman
40. 40.🔁 What number does this code show?
    let runs = [5, 7, 18, 5, 10];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);

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