App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 361 · 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 steps = [17, 4, 8];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
2. 2.🔁 What number does this code show?
   let steps = [20, 14, 5, 7];
   let best = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] > best) {
       best = steps[i];
     }
   }
   show(best);
3. 3.🔁 What number does this code show?
   let scores = [2, 13, 7];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
4. 4.🔁 What number does this code show?
   let marks = [4, 16, 13, 11, 9];
   let best = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] > best) {
       best = marks[i];
     }
   }
   show(best);
5. 5.🔁 What number does this code show?
   let runs = [14, 20, 12, 19, 10];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
6. 6.🔁 What number does this code show?
   let steps = [10, 19, 15, 12];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
7. 7.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2, 3 (b) 3 (c) 1, 2, 3 (d) 0, 1, 2
8. 8.🔁 What number does this code show?
   let scores = [15, 15, 5, 2];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
9. 9.🔁 What number does this code show?
   let runs = [1, 13, 9];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
10. 10.🔁 What number does this code show?
    let runs = [18, 78, 20, 66];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
11. 11.🔁 list.length tells you ___. (a) the first item (b) how many items it has (c) the biggest item (d) the last item
12. 12.🔁 What number does this code show?
    let marks = [12, 4, 17];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
13. 13.🔁 What number does this code show?
    let steps = [37, 51, 27];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
14. 14.🔁 What number does this code show?
    let scores = [20, 15, 17, 5, 1];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
15. 15.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Meera (c) Hi, Arjun
16. 16.🔁 What number does this code show?
    let runs = [13, 11, 19, 6, 4];
    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 scores = [13, 18, 1];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
18. 18.🔁 What number does this code show?
    let scores = [12, 9, 12, 6, 11];
    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 scores = [10, 6, 7];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
20. 20.🔁 What number does this code show?
    let scores = [18, 1, 12];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
21. 21.🔁 A loop over a list of 5 items runs its body how many times? (a) 5 (b) 6 (c) 4 (d) 1
22. 22.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Aman
23. 23.🔁 What number does this code show?
    let scores = [12, 4, 9, 1, 5];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
24. 24.🔁 What number does this code show?
    let runs = [9, 16, 17, 4, 8];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
25. 25.🔁 What number does this code show?
    let runs = [18, 15, 1, 4];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
26. 26.🔁 What number does this code show?
    let marks = [6, 16, 15, 1];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
27. 27.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Zoya", "Meera", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Aman (c) Hi, Zoya (d) Hi, Arjun
28. 28.🔁 What number does this code show?
    let marks = [14, 2, 1];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
29. 29.🔁 What number does this code show?
    let scores = [2, 4, 3, 12, 19];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
30. 30.🔁 What number does this code show?
    let runs = [6, 14, 15, 10];
    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 steps = [10, 6, 1, 18, 19];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
32. 32.🔁 Why use a loop to show 100 messages? (a) less code to write (b) it is slower (c) it uses more lines (d) it hides them
33. 33.🔁 What number does this code show?
    let runs = [11, 12, 13];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
34. 34.🔁 What number does this code show?
    let marks = [4, 17, 13];
    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 = [3, 4, 1, 4];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
36. 36.🔁 What does a loop do? (a) deletes code (b) draws icons (c) saves photos (d) repeats code
37. 37.🔁 What number does this code show?
    let steps = [76, 22, 38, 32];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
38. 38.🔁 What number does this code show?
    let steps = [4, 6, 15];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
39. 39.🔁 What number does this code show?
    let runs = [18, 16, 11, 7];
    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 marks = [10, 5, 7, 15, 20];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);

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