App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 854 · 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.🔁 Why use a loop to show 100 messages? (a) it hides them (b) it is slower (c) less code to write (d) it uses more lines
2. 2.🔁 What number does this code show?
   let scores = [61, 17, 34, 92];
   let count = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] >= 70) {
       count = count + 1;
     }
   }
   show(count);
3. 3.🔁 What is the LAST line this code shows?
   let names = ["Kabir", "Meera", "Arjun", "Riya"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Kabir (b) Hi, Riya (c) Hi, Arjun (d) Hi, Meera
4. 4.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 3 (b) 0, 1, 2 (c) 0, 1, 2, 3 (d) 1, 2, 3
5. 5.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 1 (c) 6 (d) 5
6. 6.🔁 What number does this code show?
   let marks = [3, 17, 16];
   let best = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] > best) {
       best = marks[i];
     }
   }
   show(best);
7. 7.🔁 What number does this code show?
   let marks = [8, 11, 14, 13, 5];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
8. 8.🔁 What number does this code show?
   let steps = [9, 20, 3];
   let best = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] > best) {
       best = steps[i];
     }
   }
   show(best);
9. 9.🔁 What number does this code show?
   let steps = [34, 25, 57, 79];
   let count = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
10. 10.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Zoya (c) Hi, Arjun (d) Hi, Aman
11. 11.🔁 What number does this code show?
    let marks = [12, 11, 2, 11, 13];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
12. 12.🔁 What number does this code show?
    let runs = [78, 64, 56, 63, 53];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
13. 13.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Aman (c) Hi, Arjun
14. 14.🔁 What number does this code show?
    let runs = [12, 9, 20];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
15. 15.🔁 What number does this code show?
    let runs = [16, 19, 86];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
16. 16.🔁 What number does this code show?
    let steps = [15, 11, 12, 17, 12];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
17. 17.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Meera", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Zoya (c) Hi, Meera (d) Hi, Kabir
18. 18.🔁 What number does this code show?
    let scores = [18, 13, 3, 11, 6];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
19. 19.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Aman (c) Hi, Meera
20. 20.🔁 What number does this code show?
    let scores = [10, 13, 19];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
21. 21.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Aman", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Meera (c) Hi, Zoya
22. 22.🔁 What number does this code show?
    let runs = [17, 12, 4];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
23. 23.🔁 What number does this code show?
    let marks = [15, 5, 14];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
24. 24.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Arjun", "Meera", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Riya (d) Hi, Zoya
25. 25.🔁 What number does this code show?
    let marks = [5, 6, 17];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
26. 26.🔁 What does a loop do? (a) deletes code (b) repeats code (c) draws icons (d) saves photos
27. 27.🔁 What number does this code show?
    let scores = [14, 20, 9, 9, 12];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
28. 28.🔁 What number does this code show?
    let runs = [13, 19, 16];
    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 steps = [86, 97, 51, 96, 98];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
30. 30.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Meera", "Arjun", "Kabir", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Zoya (c) Hi, Arjun (d) Hi, Meera
31. 31.🔁 What number does this code show?
    let runs = [11, 12, 13, 13, 16];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
32. 32.🔁 list.length tells you ___. (a) the last item (b) the biggest item (c) how many items it has (d) the first item
33. 33.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Arjun (c) Hi, Kabir
34. 34.🔁 What number does this code show?
    let steps = [16, 29, 33];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
35. 35.🔁 What number does this code show?
    let runs = [14, 18, 12, 14, 17];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
36. 36.🔁 What number does this code show?
    let runs = [20, 6, 5];
    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 runs = [94, 28, 16, 29];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
38. 38.🔁 What number does this code show?
    let steps = [73, 85, 28, 27];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
39. 39.🔁 What number does this code show?
    let marks = [8, 16, 6];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
40. 40.🔁 What number does this code show?
    let runs = [7, 7, 8];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);

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