App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 316 · 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 = [12, 2, 15, 14];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
2. 2.🔁 What number does this code show?
   let runs = [97, 76, 64, 29, 74];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
3. 3.🔁 What is the LAST line this code shows?
   let names = ["Aman", "Riya", "Kabir"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Kabir (b) Hi, Aman (c) Hi, Riya
4. 4.🔁 What is the LAST line this code shows?
   let names = ["Riya", "Aman", "Zoya", "Kabir", "Meera"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Aman (b) Hi, Riya (c) Hi, Meera (d) Hi, Zoya
5. 5.🔁 What number does this code show?
   let scores = [2, 2, 7, 16, 12];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
6. 6.🔁 A loop over a list of 5 items runs its body how many times? (a) 6 (b) 5 (c) 4 (d) 1
7. 7.🔁 What number does this code show?
   let runs = [72, 49, 26];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
8. 8.🔁 What number does this code show?
   let marks = [10, 6, 11, 16, 20];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
9. 9.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2, 3 (b) 0, 1, 2 (c) 3 (d) 1, 2, 3
10. 10.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Aman", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Meera (c) Hi, Riya (d) Hi, Aman
11. 11.🔁 What number does this code show?
    let marks = [13, 15, 6, 17];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
12. 12.🔁 What number does this code show?
    let runs = [25, 88, 37, 22];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
13. 13.🔁 What number does this code show?
    let runs = [46, 71, 16, 82, 29];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
14. 14.🔁 What number does this code show?
    let marks = [10, 96, 32, 11];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
15. 15.🔁 What number does this code show?
    let steps = [18, 16, 14, 12];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
16. 16.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Zoya", "Riya", "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
17. 17.🔁 What number does this code show?
    let steps = [58, 80, 26, 58];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
18. 18.🔁 What number does this code show?
    let scores = [78, 44, 30, 27, 80];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
19. 19.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Kabir", "Meera", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Meera (c) Hi, Kabir (d) Hi, Aman
20. 20.🔁 What does a loop do? (a) saves photos (b) draws icons (c) repeats code (d) deletes code
21. 21.🔁 What number does this code show?
    let scores = [20, 18, 12, 19, 12];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
22. 22.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Aman", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Aman (c) Hi, Riya (d) Hi, Meera
23. 23.🔁 What number does this code show?
    let scores = [6, 16, 1, 8];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
24. 24.🔁 What number does this code show?
    let scores = [16, 3, 3, 6];
    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 steps = [13, 13, 3, 13];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
26. 26.🔁 What number does this code show?
    let marks = [72, 13, 75, 19];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
27. 27.🔁 What number does this code show?
    let scores = [6, 2, 5];
    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 marks = [85, 46, 55];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
29. 29.🔁 What number does this code show?
    let runs = [20, 25, 13, 66, 10];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
30. 30.🔁 list.length tells you ___. (a) the first item (b) the biggest item (c) how many items it has (d) the last item
31. 31.🔁 What number does this code show?
    let runs = [16, 11, 16, 3, 1];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
32. 32.🔁 What number does this code show?
    let runs = [17, 2, 19];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
33. 33.🔁 What number does this code show?
    let marks = [3, 10, 7];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
34. 34.🔁 What number does this code show?
    let steps = [16, 6, 14, 12];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
35. 35.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Aman", "Arjun", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Aman (c) Hi, Riya (d) Hi, Kabir
36. 36.🔁 What number does this code show?
    let runs = [13, 16, 20];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
37. 37.🔁 Why use a loop to show 100 messages? (a) it uses more lines (b) it hides them (c) it is slower (d) less code to write
38. 38.🔁 What number does this code show?
    let scores = [81, 33, 87, 75, 42];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
39. 39.🔁 What number does this code show?
    let scores = [27, 88, 94, 68];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
40. 40.🔁 What number does this code show?
    let steps = [12, 3, 1, 1, 10];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);

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