App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 33 · 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 does a loop do? (a) repeats code (b) saves photos (c) draws icons (d) deletes code
2. 2.🔁 What is the LAST line this code shows?
   let names = ["Riya", "Aman", "Zoya", "Kabir"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Riya (b) Hi, Zoya (c) Hi, Aman (d) Hi, Kabir
3. 3.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 3 (b) 1, 2, 3 (c) 0, 1, 2, 3 (d) 0, 1, 2
4. 4.🔁 What number does this code show?
   let runs = [16, 9, 1];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
5. 5.🔁 Why use a loop to show 100 messages? (a) less code to write (b) it hides them (c) it uses more lines (d) it is slower
6. 6.🔁 What number does this code show?
   let runs = [8, 20, 7, 11, 14];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
7. 7.🔁 What number does this code show?
   let steps = [5, 17, 10];
   let best = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] > best) {
       best = steps[i];
     }
   }
   show(best);
8. 8.🔁 What number does this code show?
   let scores = [16, 6, 20];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
9. 9.🔁 What number does this code show?
   let marks = [12, 87, 35, 80, 81];
   let count = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] >= 70) {
       count = count + 1;
     }
   }
   show(count);
10. 10.🔁 What number does this code show?
    let scores = [95, 87, 88, 55, 78];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
11. 11.🔁 What number does this code show?
    let marks = [7, 10, 5, 3, 2];
    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 scores = [20, 2, 3, 17, 6];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
13. 13.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 1 (c) 5 (d) 6
14. 14.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Kabir", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Riya (c) Hi, Meera
15. 15.🔁 What number does this code show?
    let steps = [19, 18, 6, 11, 8];
    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 = [7, 8, 7];
    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 runs = [26, 14, 13, 66, 27];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
18. 18.🔁 What number does this code show?
    let scores = [10, 1, 15, 3, 8];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
19. 19.🔁 What number does this code show?
    let steps = [20, 15, 10, 3, 3];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
20. 20.🔁 What number does this code show?
    let steps = [87, 73, 93, 25];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
21. 21.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Zoya", "Aman", "Kabir", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Aman (c) Hi, Riya (d) Hi, Arjun
22. 22.🔁 What number does this code show?
    let steps = [20, 5, 1, 3, 13];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
23. 23.🔁 What number does this code show?
    let marks = [4, 18, 2, 5, 7];
    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 scores = [20, 17, 2, 10, 17];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
25. 25.🔁 What number does this code show?
    let runs = [2, 3, 8];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
26. 26.🔁 list.length tells you ___. (a) the last item (b) the first item (c) the biggest item (d) how many items it has
27. 27.🔁 What number does this code show?
    let steps = [9, 13, 9, 9, 15];
    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 = [4, 20, 16, 15, 7];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
29. 29.🔁 What number does this code show?
    let scores = [14, 11, 9, 7, 5];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
30. 30.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Riya", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Aman (c) Hi, Riya
31. 31.🔁 What number does this code show?
    let marks = [1, 11, 6, 6];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
32. 32.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Kabir (c) Hi, Meera
33. 33.🔁 What number does this code show?
    let scores = [11, 16, 3, 3, 5];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
34. 34.🔁 What number does this code show?
    let steps = [9, 17, 2, 16, 10];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
35. 35.🔁 What number does this code show?
    let scores = [4, 14, 3, 16];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
36. 36.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Arjun", "Aman", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Riya (c) Hi, Kabir (d) Hi, Aman
37. 37.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Kabir", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Arjun (c) Hi, Meera (d) Hi, Kabir
38. 38.🔁 What number does this code show?
    let scores = [3, 8, 19, 14];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
39. 39.🔁 What number does this code show?
    let marks = [89, 21, 17];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
40. 40.🔁 What number does this code show?
    let scores = [72, 31, 33];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);

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