App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 102 · 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 = [4, 2, 13, 20];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
2. 2.🔁 What number does this code show?
   let steps = [10, 10, 7, 9, 3];
   let best = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] > best) {
       best = steps[i];
     }
   }
   show(best);
3. 3.🔁 What is the LAST line this code shows?
   let names = ["Meera", "Zoya", "Arjun", "Aman", "Kabir"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Meera (b) Hi, Kabir (c) Hi, Zoya (d) Hi, Arjun
4. 4.🔁 What number does this code show?
   let marks = [2, 13, 19];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
5. 5.🔁 What number does this code show?
   let runs = [5, 18, 1, 14, 16];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
6. 6.🔁 A loop over a list of 5 items runs its body how many times? (a) 6 (b) 4 (c) 1 (d) 5
7. 7.🔁 What number does this code show?
   let steps = [5, 8, 5];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
8. 8.🔁 What does a loop do? (a) deletes code (b) saves photos (c) repeats code (d) draws icons
9. 9.🔁 What is the LAST line this code shows?
   let names = ["Arjun", "Zoya", "Kabir", "Riya"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Kabir (b) Hi, Riya (c) Hi, Arjun (d) Hi, Zoya
10. 10.🔁 What number does this code show?
    let marks = [2, 20, 15, 5];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
11. 11.🔁 What number does this code show?
    let scores = [13, 18, 19, 1, 15];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
12. 12.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 1, 2, 3 (b) 0, 1, 2, 3 (c) 3 (d) 0, 1, 2
13. 13.🔁 What number does this code show?
    let scores = [65, 79, 83, 86, 38];
    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 marks = [7, 9, 10, 14, 19];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
15. 15.🔁 What number does this code show?
    let scores = [13, 4, 6, 17, 3];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
16. 16.🔁 Why use a loop to show 100 messages? (a) it is slower (b) it uses more lines (c) it hides them (d) less code to write
17. 17.🔁 list.length tells you ___. (a) the last item (b) how many items it has (c) the first item (d) the biggest item
18. 18.🔁 What number does this code show?
    let scores = [4, 15, 3, 19, 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 steps = [12, 9, 3];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
20. 20.🔁 What number does this code show?
    let runs = [21, 13, 84, 28];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
21. 21.🔁 What number does this code show?
    let marks = [7, 4, 8];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
22. 22.🔁 What number does this code show?
    let scores = [14, 12, 5];
    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 steps = [2, 8, 12];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
24. 24.🔁 What number does this code show?
    let steps = [14, 17, 13];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
25. 25.🔁 What number does this code show?
    let scores = [22, 76, 88, 47];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
26. 26.🔁 What number does this code show?
    let scores = [20, 10, 7, 16, 18];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
27. 27.🔁 What number does this code show?
    let marks = [19, 10, 20, 15];
    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 runs = [98, 79, 86, 34];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
29. 29.🔁 What number does this code show?
    let steps = [16, 3, 17];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
30. 30.🔁 What number does this code show?
    let runs = [11, 5, 6, 5];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
31. 31.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Kabir", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Riya (c) Hi, Aman
32. 32.🔁 What number does this code show?
    let steps = [17, 1, 20, 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 scores = [14, 19, 4, 1, 3];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
34. 34.🔁 What number does this code show?
    let marks = [1, 16, 19, 12, 12];
    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 = [61, 98, 73];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
36. 36.🔁 What number does this code show?
    let steps = [30, 96, 88, 52, 35];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
37. 37.🔁 What number does this code show?
    let scores = [29, 40, 98, 48, 94];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
38. 38.🔁 What number does this code show?
    let scores = [57, 17, 25, 77];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
39. 39.🔁 What number does this code show?
    let runs = [13, 2, 18, 13, 1];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
40. 40.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Kabir (c) Hi, Aman

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