App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 564 · 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) 1 (b) 5 (c) 6 (d) 4
2. 2.🔁 What number does this code show?
   let steps = [19, 19, 10, 17, 7];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
3. 3.🔁 What number does this code show?
   let marks = [7, 3, 10, 1, 9];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
4. 4.🔁 What is the LAST line this code shows?
   let names = ["Kabir", "Riya", "Arjun", "Aman"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Aman (b) Hi, Kabir (c) Hi, Arjun (d) Hi, Riya
5. 5.🔁 What number does this code show?
   let marks = [7, 13, 10, 5];
   let best = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] > best) {
       best = marks[i];
     }
   }
   show(best);
6. 6.🔁 What number does this code show?
   let scores = [14, 4, 6];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
7. 7.🔁 What number does this code show?
   let scores = [79, 57, 37, 15];
   let count = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
8. 8.🔁 What is the LAST line this code shows?
   let names = ["Zoya", "Kabir", "Aman", "Riya", "Meera"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Kabir (b) Hi, Zoya (c) Hi, Meera (d) Hi, Aman
9. 9.🔁 What number does this code show?
   let runs = [14, 1, 6, 16];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
10. 10.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Riya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Riya (c) Hi, Kabir
11. 11.🔁 What number does this code show?
    let runs = [12, 19, 9];
    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 scores = [3, 8, 20];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
13. 13.🔁 What number does this code show?
    let steps = [12, 20, 8];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
14. 14.🔁 What number does this code show?
    let runs = [16, 6, 5, 15, 13];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
15. 15.🔁 What does a loop do? (a) deletes code (b) draws icons (c) repeats code (d) saves photos
16. 16.🔁 What number does this code show?
    let scores = [97, 54, 32];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
17. 17.🔁 What number does this code show?
    let steps = [49, 29, 42];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
18. 18.🔁 What number does this code show?
    let marks = [7, 17, 19];
    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 = [18, 15, 15];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
20. 20.🔁 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, Zoya (b) Hi, Meera (c) Hi, Aman
21. 21.🔁 list.length tells you ___. (a) the biggest item (b) the last item (c) the first item (d) how many items it has
22. 22.🔁 What number does this code show?
    let runs = [64, 98, 31];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
23. 23.🔁 What number does this code show?
    let marks = [85, 54, 72];
    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 marks = [12, 16, 20];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
25. 25.🔁 What number does this code show?
    let steps = [12, 17, 12];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
26. 26.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Zoya", "Kabir", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Meera (d) Hi, Kabir
27. 27.🔁 What number does this code show?
    let scores = [84, 77, 15, 74, 94];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
28. 28.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2, 3 (b) 1, 2, 3 (c) 3 (d) 0, 1, 2
29. 29.🔁 What number does this code show?
    let scores = [4, 7, 18, 11];
    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 scores = [48, 48, 83, 45, 43];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
31. 31.🔁 What number does this code show?
    let runs = [20, 15, 14, 7];
    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 runs = [3, 17, 12];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
33. 33.🔁 What number does this code show?
    let steps = [20, 1, 9, 17];
    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 = [10, 14, 4];
    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 = ["Meera", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Arjun (c) Hi, Meera
36. 36.🔁 What number does this code show?
    let runs = [3, 9, 14];
    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 marks = [97, 99, 86, 47];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
38. 38.🔁 What number does this code show?
    let scores = [70, 42, 63];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
39. 39.🔁 What number does this code show?
    let marks = [1, 15, 10, 15];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
40. 40.🔁 What number does this code show?
    let scores = [26, 77, 94];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);

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