App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 449 · 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 = [1, 5, 13, 4, 11];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
2. 2.🔁 What is the LAST line this code shows?
   let names = ["Kabir", "Arjun", "Aman", "Meera", "Riya"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Riya (b) Hi, Kabir (c) Hi, Arjun (d) Hi, Aman
3. 3.🔁 What number does this code show?
   let runs = [14, 18, 3];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
4. 4.🔁 What number does this code show?
   let runs = [62, 48, 80, 46];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 70) {
       count = count + 1;
     }
   }
   show(count);
5. 5.🔁 What number does this code show?
   let scores = [73, 16, 60];
   let count = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] >= 40) {
       count = count + 1;
     }
   }
   show(count);
6. 6.🔁 A loop over a list of 5 items runs its body how many times? (a) 6 (b) 1 (c) 5 (d) 4
7. 7.🔁 What number does this code show?
   let runs = [5, 3, 13];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
8. 8.🔁 What is the LAST line this code shows?
   let names = ["Arjun", "Riya", "Meera"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Riya (b) Hi, Arjun (c) Hi, Meera
9. 9.🔁 What number does this code show?
   let scores = [12, 11, 12];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
10. 10.🔁 What number does this code show?
    let steps = [14, 62, 24];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
11. 11.🔁 list.length tells you ___. (a) the biggest item (b) how many items it has (c) the last item (d) the first item
12. 12.🔁 What number does this code show?
    let steps = [37, 70, 22, 34];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
13. 13.🔁 What number does this code show?
    let marks = [5, 4, 3, 2];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
14. 14.🔁 What number does this code show?
    let steps = [5, 1, 19, 10, 4];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
15. 15.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Kabir", "Arjun", "Meera", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Arjun (c) Hi, Zoya (d) Hi, Kabir
16. 16.🔁 What number does this code show?
    let runs = [17, 2, 13, 8];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
17. 17.🔁 What number does this code show?
    let runs = [33, 12, 23, 13, 97];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
18. 18.🔁 What number does this code show?
    let scores = [1, 1, 11];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
19. 19.🔁 What number does this code show?
    let marks = [10, 4, 8, 11, 4];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
20. 20.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2, 3 (b) 0, 1, 2 (c) 1, 2, 3 (d) 3
21. 21.🔁 What number does this code show?
    let marks = [16, 18, 2, 2];
    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 = [53, 20, 66, 27];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
23. 23.🔁 What number does this code show?
    let runs = [13, 10, 1];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
24. 24.🔁 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, Zoya (c) Hi, Meera
25. 25.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Arjun", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Arjun (c) Hi, Riya (d) Hi, Aman
26. 26.🔁 What number does this code show?
    let steps = [18, 15, 12, 20, 11];
    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 scores = [3, 8, 2, 18, 15];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
28. 28.🔁 What does a loop do? (a) saves photos (b) draws icons (c) deletes code (d) repeats code
29. 29.🔁 What number does this code show?
    let marks = [12, 2, 10];
    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 runs = [9, 1, 9, 20];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
31. 31.🔁 Why use a loop to show 100 messages? (a) less code to write (b) it hides them (c) it uses more lines (d) it is slower
32. 32.🔁 What number does this code show?
    let scores = [19, 3, 16, 9, 3];
    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 steps = [16, 3, 9];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
34. 34.🔁 What number does this code show?
    let marks = [9, 13, 16, 1, 6];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
35. 35.🔁 What number does this code show?
    let scores = [17, 19, 9, 2, 11];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
36. 36.🔁 What number does this code show?
    let marks = [17, 1, 2, 19];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
37. 37.🔁 What number does this code show?
    let steps = [16, 7, 2];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
38. 38.🔁 What number does this code show?
    let runs = [73, 65, 17, 54];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
39. 39.🔁 What number does this code show?
    let steps = [8, 14, 8, 19];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
40. 40.🔁 What number does this code show?
    let scores = [13, 11, 6, 14];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);

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