App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 320 · 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.🔁 A loop over a list of 5 items runs its body how many times? (a) 6 (b) 1 (c) 5 (d) 4
2. 2.🔁 What number does this code show?
   let steps = [18, 13, 1, 2, 15];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
3. 3.🔁 What is the LAST line this code shows?
   let names = ["Riya", "Aman", "Zoya", "Arjun"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Riya (d) Hi, Aman
4. 4.🔁 What does a loop do? (a) draws icons (b) saves photos (c) repeats code (d) deletes code
5. 5.🔁 What number does this code show?
   let runs = [77, 87, 30, 31, 31];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
6. 6.🔁 What is the LAST line this code shows?
   let names = ["Zoya", "Aman", "Riya"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Zoya (b) Hi, Aman (c) Hi, Riya
7. 7.🔁 What number does this code show?
   let steps = [2, 10, 17, 10];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
8. 8.🔁 What number does this code show?
   let runs = [16, 17, 11];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
9. 9.🔁 What is the LAST line this code shows?
   let names = ["Aman", "Zoya", "Arjun", "Riya"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Arjun (b) Hi, Riya (c) Hi, Aman (d) Hi, Zoya
10. 10.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 3 (b) 0, 1, 2, 3 (c) 1, 2, 3 (d) 0, 1, 2
11. 11.🔁 What number does this code show?
    let scores = [6, 19, 4, 4];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
12. 12.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Zoya", "Aman", "Kabir", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Riya (c) Hi, Aman (d) Hi, Zoya
13. 13.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Meera (c) Hi, Kabir (d) Hi, Aman
14. 14.🔁 What number does this code show?
    let marks = [25, 12, 28, 38];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
15. 15.🔁 What number does this code show?
    let steps = [9, 9, 2];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
16. 16.🔁 What number does this code show?
    let steps = [11, 16, 13, 2];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
17. 17.🔁 What number does this code show?
    let scores = [17, 13, 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 marks = [13, 1, 14, 17];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
19. 19.🔁 What number does this code show?
    let scores = [1, 1, 16, 5];
    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 marks = [6, 14, 3];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
21. 21.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Zoya (c) Hi, Arjun
22. 22.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Riya", "Kabir", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Zoya (c) Hi, Aman (d) Hi, Kabir
23. 23.🔁 What number does this code show?
    let marks = [2, 12, 9];
    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 = [2, 1, 7];
    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 = [63, 27, 49];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
26. 26.🔁 What number does this code show?
    let marks = [69, 83, 96, 98, 60];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
27. 27.🔁 list.length tells you ___. (a) the biggest item (b) how many items it has (c) the first item (d) the last item
28. 28.🔁 What number does this code show?
    let runs = [4, 9, 6, 1];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
29. 29.🔁 What number does this code show?
    let scores = [4, 19, 1];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
30. 30.🔁 What number does this code show?
    let runs = [17, 10, 4, 8];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
31. 31.🔁 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
32. 32.🔁 What number does this code show?
    let marks = [7, 7, 10];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
33. 33.🔁 What number does this code show?
    let marks = [6, 11, 17];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
34. 34.🔁 What number does this code show?
    let scores = [12, 4, 3];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
35. 35.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Zoya (c) Hi, Meera
36. 36.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Aman", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Riya (c) Hi, Meera
37. 37.🔁 What number does this code show?
    let scores = [6, 20, 5, 10];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
38. 38.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Riya (c) Hi, Zoya
39. 39.🔁 What number does this code show?
    let runs = [16, 4, 17];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
40. 40.🔁 What number does this code show?
    let runs = [24, 42, 22, 45, 77];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);

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