App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 725 · 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 scores = [60, 61, 22, 31, 21];
   let count = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
2. 2.🔁 What number does this code show?
   let steps = [11, 5, 17];
   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 runs = [54, 84, 94, 19, 30];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 40) {
       count = count + 1;
     }
   }
   show(count);
4. 4.🔁 What number does this code show?
   let marks = [30, 47, 37, 63, 78];
   let count = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] >= 70) {
       count = count + 1;
     }
   }
   show(count);
5. 5.🔁 What number does this code show?
   let runs = [44, 67, 35];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
6. 6.🔁 What number does this code show?
   let marks = [13, 1, 5, 4];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
7. 7.🔁 What does a loop do? (a) repeats code (b) saves photos (c) deletes code (d) draws icons
8. 8.🔁 What is the LAST line this code shows?
   let names = ["Riya", "Aman", "Zoya"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Aman (b) Hi, Riya (c) Hi, Zoya
9. 9.🔁 What number does this code show?
   let runs = [16, 3, 8, 6];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
10. 10.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Kabir", "Zoya", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Aman (d) Hi, Kabir
11. 11.🔁 Why use a loop to show 100 messages? (a) it uses more lines (b) it is slower (c) less code to write (d) it hides them
12. 12.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Aman (c) Hi, Zoya
13. 13.🔁 What number does this code show?
    let scores = [17, 10, 2, 5, 5];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
14. 14.🔁 What number does this code show?
    let marks = [16, 13, 15, 15, 17];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
15. 15.🔁 What number does this code show?
    let marks = [6, 8, 6];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
16. 16.🔁 What number does this code show?
    let steps = [13, 4, 18];
    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 marks = [4, 3, 14, 15, 18];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
18. 18.🔁 What number does this code show?
    let scores = [3, 5, 11];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
19. 19.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 1 (c) 6 (d) 5
20. 20.🔁 What number does this code show?
    let scores = [3, 3, 8, 6, 11];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
21. 21.🔁 What number does this code show?
    let runs = [64, 49, 57];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
22. 22.🔁 What number does this code show?
    let runs = [15, 18, 6];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
23. 23.🔁 What number does this code show?
    let steps = [63, 97, 79];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
24. 24.🔁 What number does this code show?
    let marks = [3, 9, 2];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
25. 25.🔁 What number does this code show?
    let scores = [16, 9, 15, 1];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
26. 26.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Arjun", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Riya (c) Hi, Aman
27. 27.🔁 What number does this code show?
    let runs = [1, 1, 16, 8];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
28. 28.🔁 What number does this code show?
    let marks = [77, 73, 60, 68];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
29. 29.🔁 What number does this code show?
    let scores = [17, 6, 14, 6, 1];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
30. 30.🔁 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
31. 31.🔁 What number does this code show?
    let marks = [20, 48, 63, 79, 36];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
32. 32.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Kabir", "Riya", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Riya (c) Hi, Kabir (d) Hi, Arjun
33. 33.🔁 What number does this code show?
    let runs = [19, 2, 6];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
34. 34.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Zoya", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Riya (c) Hi, Kabir (d) Hi, Zoya
35. 35.🔁 What number does this code show?
    let scores = [90, 71, 31, 96, 11];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
36. 36.🔁 What number does this code show?
    let marks = [15, 2, 20];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
37. 37.🔁 What number does this code show?
    let marks = [51, 99, 88, 16, 23];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
38. 38.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2 (b) 3 (c) 1, 2, 3 (d) 0, 1, 2, 3
39. 39.🔁 What number does this code show?
    let marks = [10, 2, 9, 5, 18];
    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 runs = [15, 7, 16, 4, 13];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);

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