App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 726 · 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 = [12, 6, 1, 12];
   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 marks = [20, 7, 2, 15, 4];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
3. 3.🔁 What number does this code show?
   let marks = [1, 5, 11, 9, 15];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
4. 4.🔁 What number does this code show?
   let scores = [72, 89, 11, 34];
   let count = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] >= 70) {
       count = count + 1;
     }
   }
   show(count);
5. 5.🔁 What number does this code show?
   let steps = [7, 6, 7, 16];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
6. 6.🔁 What is the LAST line this code shows?
   let names = ["Meera", "Riya", "Aman"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Meera (b) Hi, Aman (c) Hi, Riya
7. 7.🔁 What number does this code show?
   let runs = [8, 2, 14];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
8. 8.🔁 What does a loop do? (a) saves photos (b) draws icons (c) deletes code (d) repeats code
9. 9.🔁 A loop over a list of 5 items runs its body how many times? (a) 1 (b) 5 (c) 4 (d) 6
10. 10.🔁 What number does this code show?
    let marks = [14, 19, 6];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
11. 11.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Kabir", "Zoya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Meera (c) Hi, Zoya (d) Hi, Kabir
12. 12.🔁 What number does this code show?
    let runs = [7, 7, 5];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
13. 13.🔁 What number does this code show?
    let scores = [72, 13, 52, 47];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
14. 14.🔁 What number does this code show?
    let runs = [13, 3, 19];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
15. 15.🔁 What number does this code show?
    let marks = [77, 49, 83];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
16. 16.🔁 What number does this code show?
    let scores = [1, 8, 5];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
17. 17.🔁 What number does this code show?
    let steps = [53, 33, 76];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
18. 18.🔁 What number does this code show?
    let steps = [9, 20, 2, 16];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
19. 19.🔁 What number does this code show?
    let marks = [94, 98, 18, 97];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
20. 20.🔁 What number does this code show?
    let scores = [56, 59, 31, 27, 46];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
21. 21.🔁 What number does this code show?
    let scores = [18, 18, 4, 6];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
22. 22.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 1, 2, 3 (b) 3 (c) 0, 1, 2 (d) 0, 1, 2, 3
23. 23.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Meera (c) Hi, Zoya
24. 24.🔁 What number does this code show?
    let marks = [37, 25, 84, 31];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
25. 25.🔁 What number does this code show?
    let marks = [61, 39, 62];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
26. 26.🔁 list.length tells you ___. (a) the last item (b) how many items it has (c) the first item (d) the biggest item
27. 27.🔁 What number does this code show?
    let marks = [6, 6, 3];
    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 steps = [5, 13, 19];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
29. 29.🔁 What number does this code show?
    let steps = [5, 19, 20];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
30. 30.🔁 What number does this code show?
    let marks = [2, 20, 10, 20, 14];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
31. 31.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Meera", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Riya (c) Hi, Kabir
32. 32.🔁 What number does this code show?
    let runs = [18, 1, 7];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
33. 33.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Riya", "Zoya", "Kabir", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Aman (d) Hi, Riya
34. 34.🔁 What number does this code show?
    let steps = [46, 86, 40, 77, 66];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
35. 35.🔁 What number does this code show?
    let scores = [3, 6, 4];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
36. 36.🔁 Why use a loop to show 100 messages? (a) it uses more lines (b) less code to write (c) it hides them (d) it is slower
37. 37.🔁 What number does this code show?
    let marks = [20, 13, 14, 8, 9];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
38. 38.🔁 What number does this code show?
    let steps = [98, 86, 57, 66];
    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 = ["Meera", "Riya", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Riya (d) Hi, Meera
40. 40.🔁 What number does this code show?
    let scores = [20, 15, 20, 9];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);

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