App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 308 · 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 marks = [35, 97, 78, 90, 42];
   let count = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] >= 40) {
       count = count + 1;
     }
   }
   show(count);
2. 2.🔁 What number does this code show?
   let steps = [52, 57, 86, 67, 53];
   let count = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] >= 40) {
       count = count + 1;
     }
   }
   show(count);
3. 3.🔁 What number does this code show?
   let marks = [10, 2, 16];
   let best = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] > best) {
       best = marks[i];
     }
   }
   show(best);
4. 4.🔁 A loop over a list of 5 items runs its body how many times? (a) 1 (b) 5 (c) 4 (d) 6
5. 5.🔁 What is the LAST line this code shows?
   let names = ["Zoya", "Riya", "Kabir"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Riya (b) Hi, Kabir (c) Hi, Zoya
6. 6.🔁 What is the LAST line this code shows?
   let names = ["Riya", "Meera", "Aman", "Kabir"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Riya (b) Hi, Kabir (c) Hi, Meera (d) Hi, Aman
7. 7.🔁 What number does this code show?
   let runs = [11, 18, 18, 1, 19];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
8. 8.🔁 What does a loop do? (a) saves photos (b) draws icons (c) deletes code (d) repeats code
9. 9.🔁 What number does this code show?
   let scores = [6, 17, 16];
   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 scores = [12, 20, 12];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
11. 11.🔁 What number does this code show?
    let scores = [19, 34, 62];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
12. 12.🔁 list.length tells you ___. (a) the last item (b) the biggest item (c) how many items it has (d) the first item
13. 13.🔁 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, Aman (b) Hi, Riya (c) Hi, Meera
14. 14.🔁 What number does this code show?
    let marks = [14, 13, 20, 18, 7];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
15. 15.🔁 What number does this code show?
    let marks = [12, 13, 13];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
16. 16.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Kabir", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Arjun (c) Hi, Riya (d) Hi, Kabir
17. 17.🔁 What number does this code show?
    let steps = [1, 8, 6, 18, 18];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
18. 18.🔁 What number does this code show?
    let runs = [2, 10, 16];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
19. 19.🔁 What number does this code show?
    let marks = [17, 19, 8, 9, 12];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
20. 20.🔁 What number does this code show?
    let steps = [13, 3, 20, 2];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
21. 21.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Zoya", "Arjun", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Zoya (c) Hi, Meera (d) Hi, Kabir
22. 22.🔁 What number does this code show?
    let scores = [14, 2, 11, 13];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
23. 23.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Riya (c) Hi, Arjun
24. 24.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Kabir", "Arjun", "Riya", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Zoya (c) Hi, Arjun (d) Hi, Kabir
25. 25.🔁 What number does this code show?
    let scores = [7, 19, 17, 3];
    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 runs = [68, 63, 50, 19];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
27. 27.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Kabir", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Kabir (c) Hi, Aman
28. 28.🔁 What number does this code show?
    let scores = [20, 13, 6];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
29. 29.🔁 What number does this code show?
    let marks = [64, 79, 31];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
30. 30.🔁 What number does this code show?
    let runs = [18, 2, 5, 5, 11];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
31. 31.🔁 What number does this code show?
    let scores = [4, 15, 10, 12];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
32. 32.🔁 What number does this code show?
    let scores = [12, 20, 20, 2];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
33. 33.🔁 Why use a loop to show 100 messages? (a) it uses more lines (b) less code to write (c) it is slower (d) it hides them
34. 34.🔁 What number does this code show?
    let steps = [14, 16, 16, 17];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
35. 35.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Meera", "Aman", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Aman (c) Hi, Meera (d) Hi, Riya
36. 36.🔁 What number does this code show?
    let marks = [18, 18, 20];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
37. 37.🔁 What number does this code show?
    let steps = [13, 4, 17, 4];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
38. 38.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Kabir (c) Hi, Aman
39. 39.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 1, 2, 3 (b) 0, 1, 2, 3 (c) 0, 1, 2 (d) 3
40. 40.🔁 What number does this code show?
    let steps = [20, 4, 10, 12];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);

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