App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 141 · 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 = [16, 14, 9];
   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 steps = [11, 3, 3];
   let best = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] > best) {
       best = steps[i];
     }
   }
   show(best);
3. 3.🔁 What number does this code show?
   let steps = [8, 9, 20, 8, 12];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
4. 4.🔁 What does a loop do? (a) saves photos (b) repeats code (c) deletes code (d) draws icons
5. 5.🔁 What number does this code show?
   let steps = [61, 45, 80, 65];
   let count = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
6. 6.🔁 What number does this code show?
   let marks = [99, 60, 80, 61];
   let count = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
7. 7.🔁 What number does this code show?
   let marks = [29, 84, 57, 34];
   let count = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
8. 8.🔁 What number does this code show?
   let marks = [20, 11, 7, 2, 17];
   let best = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] > best) {
       best = marks[i];
     }
   }
   show(best);
9. 9.🔁 What number does this code show?
   let scores = [9, 1, 15, 15];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
10. 10.🔁 A loop over a list of 5 items runs its body how many times? (a) 1 (b) 6 (c) 4 (d) 5
11. 11.🔁 What number does this code show?
    let scores = [5, 11, 17];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
12. 12.🔁 Why use a loop to show 100 messages? (a) it is slower (b) less code to write (c) it hides them (d) it uses more lines
13. 13.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Kabir", "Riya", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Arjun (c) Hi, Riya (d) Hi, Kabir
14. 14.🔁 What number does this code show?
    let marks = [17, 12, 10, 19];
    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 runs = [7, 11, 20];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
16. 16.🔁 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, Meera (c) Hi, Arjun (d) Hi, Riya
17. 17.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Arjun", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Aman
18. 18.🔁 What number does this code show?
    let marks = [3, 9, 11];
    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 = [13, 54, 67, 56, 38];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
20. 20.🔁 What number does this code show?
    let scores = [19, 26, 77, 50];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
21. 21.🔁 What number does this code show?
    let steps = [17, 11, 2];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
22. 22.🔁 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, Meera (c) Hi, Riya
23. 23.🔁 What number does this code show?
    let scores = [32, 41, 11];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
24. 24.🔁 What number does this code show?
    let steps = [3, 10, 14];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
25. 25.🔁 What number does this code show?
    let runs = [57, 21, 41, 38];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
26. 26.🔁 What number does this code show?
    let runs = [80, 14, 14, 89];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
27. 27.🔁 What number does this code show?
    let steps = [88, 77, 10, 43, 82];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
28. 28.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Kabir", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Meera (c) Hi, Arjun (d) Hi, Kabir
29. 29.🔁 What number does this code show?
    let runs = [8, 3, 11];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
30. 30.🔁 What number does this code show?
    let scores = [8, 4, 3, 6];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
31. 31.🔁 What number does this code show?
    let marks = [3, 1, 4];
    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", "Arjun", "Aman", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Meera (c) Hi, Arjun (d) Hi, Kabir
33. 33.🔁 What number does this code show?
    let steps = [2, 10, 20, 4, 9];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
34. 34.🔁 What number does this code show?
    let runs = [9, 6, 7, 2];
    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 scores = [5, 7, 14, 6, 9];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
36. 36.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 1, 2, 3 (b) 0, 1, 2 (c) 0, 1, 2, 3 (d) 3
37. 37.🔁 What number does this code show?
    let scores = [9, 4, 11];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
38. 38.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Aman", "Meera", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Aman (c) Hi, Arjun (d) Hi, Riya
39. 39.🔁 What number does this code show?
    let marks = [13, 3, 9, 4];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
40. 40.🔁 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, Zoya (b) Hi, Kabir (c) Hi, Riya (d) Hi, Aman

Free app development lessons, practice and worksheets at talentjr.in/app-development-for-students