App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 202 · 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 = [1, 15, 7, 5];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
2. 2.🔁 What number does this code show?
   let marks = [10, 18, 17];
   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 steps = [4, 15, 2, 17, 12];
   let best = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] > best) {
       best = steps[i];
     }
   }
   show(best);
4. 4.🔁 What number does this code show?
   let runs = [67, 99, 12, 99, 28];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 40) {
       count = count + 1;
     }
   }
   show(count);
5. 5.🔁 What number does this code show?
   let marks = [15, 7, 17];
   let best = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] > best) {
       best = marks[i];
     }
   }
   show(best);
6. 6.🔁 What number does this code show?
   let runs = [21, 52, 90, 96];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
7. 7.🔁 What number does this code show?
   let scores = [2, 3, 5, 20, 4];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
8. 8.🔁 What does a loop do? (a) saves photos (b) draws icons (c) repeats code (d) deletes code
9. 9.🔁 What is the LAST line this code shows?
   let names = ["Zoya", "Kabir", "Arjun"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Kabir (b) Hi, Zoya (c) Hi, Arjun
10. 10.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Aman", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Arjun (c) Hi, Zoya (d) Hi, Meera
11. 11.🔁 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, Kabir (b) Hi, Zoya (c) Hi, Arjun
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) 0, 1, 2 (d) 3
13. 13.🔁 What number does this code show?
    let steps = [14, 4, 13];
    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 marks = [37, 45, 97];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
15. 15.🔁 What number does this code show?
    let scores = [9, 8, 8, 6];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
16. 16.🔁 What number does this code show?
    let runs = [10, 10, 15, 1, 20];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
17. 17.🔁 Why use a loop to show 100 messages? (a) less code to write (b) it uses more lines (c) it hides them (d) it is slower
18. 18.🔁 What number does this code show?
    let marks = [32, 95, 80, 62, 40];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
19. 19.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Riya", "Zoya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Aman (c) Hi, Riya (d) Hi, Arjun
20. 20.🔁 What number does this code show?
    let runs = [31, 19, 60];
    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 steps = [5, 12, 5, 8];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
22. 22.🔁 What number does this code show?
    let scores = [1, 10, 7];
    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 scores = [2, 12, 3];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
24. 24.🔁 A loop over a list of 5 items runs its body how many times? (a) 6 (b) 1 (c) 4 (d) 5
25. 25.🔁 What number does this code show?
    let marks = [81, 83, 79];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
26. 26.🔁 What number does this code show?
    let runs = [40, 59, 50, 11];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
27. 27.🔁 What number does this code show?
    let steps = [13, 27, 35, 69, 58];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
28. 28.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Aman", "Meera", "Kabir", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Riya (c) Hi, Zoya (d) Hi, Meera
29. 29.🔁 list.length tells you ___. (a) the biggest item (b) how many items it has (c) the first item (d) the last item
30. 30.🔁 What number does this code show?
    let scores = [1, 1, 14, 15, 17];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
31. 31.🔁 What number does this code show?
    let marks = [11, 82, 38];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
32. 32.🔁 What number does this code show?
    let scores = [12, 54, 40];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
33. 33.🔁 What number does this code show?
    let scores = [87, 64, 46, 42, 57];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
34. 34.🔁 What number does this code show?
    let marks = [20, 11, 1, 4, 19];
    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 = [90, 98, 34];
    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 = [14, 4, 4, 19];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
37. 37.🔁 What number does this code show?
    let runs = [18, 72, 11, 34, 41];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
38. 38.🔁 What number does this code show?
    let scores = [22, 11, 90];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
39. 39.🔁 What number does this code show?
    let runs = [2, 1, 20];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
40. 40.🔁 What number does this code show?
    let scores = [13, 10, 14, 12, 2];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);

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