App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 989 · 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 steps = [4, 17, 2, 19, 4];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
2. 2.🔁 What number does this code show?
   let scores = [18, 14, 7, 3, 8];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
3. 3.🔁 What number does this code show?
   let marks = [4, 15, 6];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
4. 4.🔁 What number does this code show?
   let runs = [29, 16, 23];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
5. 5.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 6 (c) 5 (d) 1
6. 6.🔁 What number does this code show?
   let marks = [58, 89, 65];
   let count = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] >= 40) {
       count = count + 1;
     }
   }
   show(count);
7. 7.🔁 What is the LAST line this code shows?
   let names = ["Zoya", "Meera", "Riya", "Aman"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Aman (b) Hi, Riya (c) Hi, Zoya (d) Hi, Meera
8. 8.🔁 What number does this code show?
   let runs = [13, 20, 15, 18, 6];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
9. 9.🔁 What number does this code show?
   let steps = [10, 2, 17];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
10. 10.🔁 What number does this code show?
    let runs = [41, 50, 79, 88, 47];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
11. 11.🔁 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
12. 12.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Arjun", "Aman", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Meera (c) Hi, Aman (d) Hi, Arjun
13. 13.🔁 What number does this code show?
    let scores = [8, 10, 15];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
14. 14.🔁 What number does this code show?
    let marks = [18, 5, 3, 12];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
15. 15.🔁 What number does this code show?
    let steps = [4, 15, 6];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
16. 16.🔁 list.length tells you ___. (a) the first item (b) the biggest item (c) the last item (d) how many items it has
17. 17.🔁 What number does this code show?
    let runs = [14, 2, 6];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
18. 18.🔁 What number does this code show?
    let scores = [19, 17, 16, 17, 18];
    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 scores = [1, 12, 17, 13, 10];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
20. 20.🔁 What number does this code show?
    let runs = [63, 86, 68, 26];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
21. 21.🔁 What number does this code show?
    let runs = [26, 89, 10];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
22. 22.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Zoya", "Riya", "Kabir", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Meera (c) Hi, Aman (d) Hi, Zoya
23. 23.🔁 What does a loop do? (a) deletes code (b) draws icons (c) saves photos (d) repeats code
24. 24.🔁 What number does this code show?
    let marks = [2, 18, 5];
    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 marks = [93, 66, 19, 52, 97];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
26. 26.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Meera", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Meera (c) Hi, Kabir
27. 27.🔁 What number does this code show?
    let steps = [18, 12, 1];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
28. 28.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Kabir", "Meera", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Riya (c) Hi, Zoya (d) Hi, Meera
29. 29.🔁 What number does this code show?
    let steps = [9, 1, 8];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
30. 30.🔁 What number does this code show?
    let steps = [90, 66, 84, 55];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
31. 31.🔁 What number does this code show?
    let runs = [18, 11, 7];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
32. 32.🔁 What number does this code show?
    let scores = [20, 9, 1];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
33. 33.🔁 What number does this code show?
    let runs = [11, 12, 7];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
34. 34.🔁 What number does this code show?
    let runs = [2, 19, 2, 7, 12];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
35. 35.🔁 What number does this code show?
    let steps = [4, 14, 2];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
36. 36.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Kabir", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Aman (c) Hi, Kabir
37. 37.🔁 What number does this code show?
    let steps = [91, 14, 26];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
38. 38.🔁 What number does this code show?
    let marks = [3, 8, 6, 15, 14];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
39. 39.🔁 What number does this code show?
    let steps = [17, 10, 19];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
40. 40.🔁 What number does this code show?
    let runs = [9, 1, 17, 4, 9];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);

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