App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 545 · 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 is the LAST line this code shows?
   let names = ["Riya", "Meera", "Zoya", "Aman"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Meera (b) Hi, Riya (c) Hi, Zoya (d) Hi, Aman
2. 2.🔁 What number does this code show?
   let steps = [11, 2, 4];
   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 = ["Riya", "Kabir", "Aman", "Meera"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Riya (b) Hi, Kabir (c) Hi, Aman (d) Hi, Meera
4. 4.🔁 What number does this code show?
   let scores = [6, 3, 3];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
5. 5.🔁 What number does this code show?
   let scores = [17, 6, 16];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
6. 6.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 3 (b) 0, 1, 2, 3 (c) 0, 1, 2 (d) 1, 2, 3
7. 7.🔁 What number does this code show?
   let marks = [7, 14, 20, 4];
   let best = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] > best) {
       best = marks[i];
     }
   }
   show(best);
8. 8.🔁 What number does this code show?
   let steps = [15, 10, 16];
   let best = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] > best) {
       best = steps[i];
     }
   }
   show(best);
9. 9.🔁 What is the LAST line this code shows?
   let names = ["Arjun", "Kabir", "Riya", "Meera"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Kabir (b) Hi, Meera (c) Hi, Arjun (d) Hi, Riya
10. 10.🔁 What number does this code show?
    let scores = [11, 19, 6];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
11. 11.🔁 list.length tells you ___. (a) the last item (b) the first item (c) how many items it has (d) the biggest item
12. 12.🔁 What number does this code show?
    let runs = [32, 37, 31];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
13. 13.🔁 What number does this code show?
    let runs = [6, 13, 7];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
14. 14.🔁 What number does this code show?
    let marks = [47, 94, 32, 94, 35];
    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 steps = [4, 3, 17, 5, 14];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
16. 16.🔁 What number does this code show?
    let marks = [20, 69, 81, 58];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
17. 17.🔁 What number does this code show?
    let runs = [11, 5, 13, 1];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
18. 18.🔁 A loop over a list of 5 items runs its body how many times? (a) 5 (b) 4 (c) 1 (d) 6
19. 19.🔁 What number does this code show?
    let marks = [11, 5, 2, 12, 15];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
20. 20.🔁 What number does this code show?
    let marks = [58, 16, 48];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
21. 21.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Arjun", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Meera (c) Hi, Riya (d) Hi, Aman
22. 22.🔁 What number does this code show?
    let marks = [2, 10, 1];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
23. 23.🔁 What number does this code show?
    let marks = [34, 33, 72];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
24. 24.🔁 What number does this code show?
    let runs = [13, 75, 86, 76];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
25. 25.🔁 What number does this code show?
    let steps = [25, 53, 20, 49];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
26. 26.🔁 Why use a loop to show 100 messages? (a) it hides them (b) it is slower (c) it uses more lines (d) less code to write
27. 27.🔁 What number does this code show?
    let runs = [80, 26, 16, 71, 26];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
28. 28.🔁 What number does this code show?
    let scores = [20, 18, 3];
    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 = [46, 73, 21];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
30. 30.🔁 What number does this code show?
    let marks = [1, 13, 4];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
31. 31.🔁 What number does this code show?
    let marks = [4, 11, 8];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
32. 32.🔁 What number does this code show?
    let scores = [11, 16, 9, 1];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
33. 33.🔁 What number does this code show?
    let marks = [26, 46, 61, 18];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
34. 34.🔁 What number does this code show?
    let runs = [4, 3, 9, 15];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
35. 35.🔁 What number does this code show?
    let runs = [31, 37, 95];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
36. 36.🔁 What number does this code show?
    let runs = [17, 14, 7];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
37. 37.🔁 What number does this code show?
    let steps = [2, 4, 15, 10];
    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 steps = [34, 61, 51];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
39. 39.🔁 What number does this code show?
    let scores = [14, 5, 17, 8];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
40. 40.🔁 What number does this code show?
    let scores = [94, 52, 20, 43];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);

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