App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 695 · 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.🔁 list.length tells you ___. (a) the last item (b) the biggest item (c) how many items it has (d) the first item
2. 2.🔁 What number does this code show?
   let marks = [18, 3, 11, 7];
   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 runs = [4, 5, 16, 5, 17];
   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 scores = [19, 18, 20, 12, 19];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
5. 5.🔁 What number does this code show?
   let scores = [10, 6, 18, 12, 5];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
6. 6.🔁 What number does this code show?
   let runs = [65, 33, 63];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
7. 7.🔁 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
8. 8.🔁 What number does this code show?
   let marks = [11, 16, 1];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
9. 9.🔁 What number does this code show?
   let runs = [8, 10, 5];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
10. 10.🔁 What number does this code show?
    let steps = [4, 2, 12, 12];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
11. 11.🔁 What number does this code show?
    let runs = [2, 16, 5];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
12. 12.🔁 What number does this code show?
    let runs = [12, 6, 2];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
13. 13.🔁 What number does this code show?
    let runs = [10, 5, 16];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
14. 14.🔁 What number does this code show?
    let marks = [30, 25, 14, 22, 42];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
15. 15.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Meera", "Kabir", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Arjun (c) Hi, Kabir (d) Hi, Aman
16. 16.🔁 What number does this code show?
    let scores = [17, 6, 10, 11, 3];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
17. 17.🔁 What does a loop do? (a) saves photos (b) deletes code (c) repeats code (d) draws icons
18. 18.🔁 What number does this code show?
    let steps = [9, 5, 13, 6];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
19. 19.🔁 Why use a loop to show 100 messages? (a) it uses more lines (b) less code to write (c) it hides them (d) it is slower
20. 20.🔁 What number does this code show?
    let steps = [2, 10, 5, 3, 6];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
21. 21.🔁 What number does this code show?
    let scores = [10, 6, 11, 12, 12];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
22. 22.🔁 What number does this code show?
    let runs = [10, 5, 1, 12];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
23. 23.🔁 What number does this code show?
    let marks = [81, 32, 83];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
24. 24.🔁 What number does this code show?
    let runs = [20, 7, 7, 3];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
25. 25.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Aman", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Meera (c) Hi, Zoya
26. 26.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Kabir", "Arjun", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Arjun (c) Hi, Kabir (d) Hi, Aman
27. 27.🔁 What number does this code show?
    let steps = [3, 16, 11, 3, 16];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
28. 28.🔁 What number does this code show?
    let marks = [7, 13, 15, 3];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
29. 29.🔁 What number does this code show?
    let scores = [22, 31, 26, 11, 89];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
30. 30.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Aman", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Riya (c) Hi, Arjun (d) Hi, Aman
31. 31.🔁 What number does this code show?
    let runs = [11, 4, 12, 17];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
32. 32.🔁 What number does this code show?
    let scores = [2, 5, 15];
    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 runs = [19, 6, 1, 11];
    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 = [1, 4, 11, 14, 18];
    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 marks = [7, 2, 5];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
36. 36.🔁 What number does this code show?
    let steps = [20, 6, 5, 11];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
37. 37.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Aman", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Zoya (c) Hi, Aman
38. 38.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Kabir (c) Hi, Arjun
39. 39.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Meera", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Kabir (c) Hi, Meera
40. 40.🔁 What number does this code show?
    let runs = [19, 7, 1, 20];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);

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