App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 891 · 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 = [14, 4, 17];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
2. 2.🔁 What is the LAST line this code shows?
   let names = ["Riya", "Zoya", "Aman"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Zoya (b) Hi, Aman (c) Hi, Riya
3. 3.🔁 What number does this code show?
   let scores = [20, 6, 5];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
4. 4.🔁 What number does this code show?
   let marks = [12, 15, 19, 7];
   let best = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] > best) {
       best = marks[i];
     }
   }
   show(best);
5. 5.🔁 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, Arjun (b) Hi, Meera (c) Hi, Riya
6. 6.🔁 What is the LAST line this code shows?
   let names = ["Aman", "Kabir", "Arjun"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Arjun (b) Hi, Aman (c) Hi, Kabir
7. 7.🔁 What number does this code show?
   let runs = [71, 59, 12];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
8. 8.🔁 What number does this code show?
   let runs = [5, 17, 10];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
9. 9.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 5 (c) 6 (d) 1
10. 10.🔁 What number does this code show?
    let marks = [54, 81, 40];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
11. 11.🔁 What number does this code show?
    let steps = [12, 7, 16, 1, 8];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
12. 12.🔁 What number does this code show?
    let steps = [2, 8, 11, 15, 6];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
13. 13.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Aman", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Kabir (c) Hi, Aman
14. 14.🔁 What number does this code show?
    let scores = [3, 2, 13, 2, 9];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
15. 15.🔁 What number does this code show?
    let scores = [11, 10, 20, 15, 10];
    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 = [11, 13, 14];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
17. 17.🔁 What number does this code show?
    let marks = [4, 3, 6];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
18. 18.🔁 What does a loop do? (a) draws icons (b) saves photos (c) deletes code (d) repeats code
19. 19.🔁 What number does this code show?
    let scores = [6, 18, 14];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
20. 20.🔁 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
21. 21.🔁 What number does this code show?
    let marks = [12, 1, 13, 20, 20];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
22. 22.🔁 What number does this code show?
    let scores = [15, 5, 13, 4, 12];
    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 marks = [2, 10, 3, 16];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
24. 24.🔁 What number does this code show?
    let runs = [8, 10, 4, 7, 13];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
25. 25.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Kabir", "Arjun", "Meera", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Zoya (d) Hi, Aman
26. 26.🔁 What number does this code show?
    let scores = [7, 20, 6];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
27. 27.🔁 What number does this code show?
    let steps = [2, 10, 19, 18];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
28. 28.🔁 What number does this code show?
    let runs = [18, 2, 20, 4, 12];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
29. 29.🔁 What number does this code show?
    let steps = [78, 74, 49, 53];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
30. 30.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Aman", "Meera", "Riya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Kabir (c) Hi, Arjun (d) Hi, Aman
31. 31.🔁 What number does this code show?
    let steps = [14, 6, 2];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
32. 32.🔁 What number does this code show?
    let steps = [84, 38, 74, 74];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
33. 33.🔁 What number does this code show?
    let steps = [12, 14, 12, 7, 5];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
34. 34.🔁 What number does this code show?
    let runs = [9, 12, 13];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
35. 35.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Aman", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Arjun (c) Hi, Riya
36. 36.🔁 What number does this code show?
    let scores = [3, 15, 18];
    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 scores = [57, 93, 91];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
38. 38.🔁 What number does this code show?
    let scores = [17, 1, 15, 1, 11];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
39. 39.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2, 3 (b) 1, 2, 3 (c) 0, 1, 2 (d) 3
40. 40.🔁 What number does this code show?
    let runs = [91, 27, 53, 35];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);

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