App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 489 · 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 = [6, 4, 13];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
2. 2.🔁 What is the LAST line this code shows?
   let names = ["Meera", "Riya", "Kabir", "Aman"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Meera (b) Hi, Kabir (c) Hi, Riya (d) Hi, Aman
3. 3.🔁 What does a loop do? (a) draws icons (b) deletes code (c) saves photos (d) repeats code
4. 4.🔁 What number does this code show?
   let runs = [29, 50, 22, 15, 89];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 40) {
       count = count + 1;
     }
   }
   show(count);
5. 5.🔁 What number does this code show?
   let scores = [7, 10, 4, 2, 10];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
6. 6.🔁 What number does this code show?
   let steps = [1, 20, 16, 20, 6];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
7. 7.🔁 What number does this code show?
   let runs = [14, 11, 16];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
8. 8.🔁 What number does this code show?
   let steps = [62, 11, 99, 88];
   let count = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
9. 9.🔁 What is the LAST line this code shows?
   let names = ["Aman", "Zoya", "Meera", "Kabir", "Arjun"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Meera (b) Hi, Zoya (c) Hi, Arjun (d) Hi, Aman
10. 10.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Zoya", "Kabir", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Aman (c) Hi, Meera (d) Hi, Arjun
11. 11.🔁 What number does this code show?
    let marks = [4, 11, 19, 3];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
12. 12.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Riya", "Aman", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Arjun (c) Hi, Zoya (d) Hi, Riya
13. 13.🔁 What number does this code show?
    let marks = [27, 84, 57, 63, 16];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
14. 14.🔁 What number does this code show?
    let runs = [20, 91, 27, 88];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
15. 15.🔁 list.length tells you ___. (a) the biggest item (b) the last item (c) how many items it has (d) the first item
16. 16.🔁 What number does this code show?
    let steps = [3, 18, 15, 10];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
17. 17.🔁 What number does this code show?
    let marks = [11, 4, 17, 16, 2];
    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 marks = [1, 20, 4, 19];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
19. 19.🔁 What number does this code show?
    let runs = [17, 7, 11, 13];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
20. 20.🔁 What number does this code show?
    let steps = [49, 25, 81];
    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 = ["Zoya", "Riya", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Aman (c) Hi, Riya (d) Hi, Zoya
22. 22.🔁 What number does this code show?
    let scores = [13, 8, 1];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
23. 23.🔁 What number does this code show?
    let scores = [62, 62, 75, 27];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
24. 24.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Zoya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Zoya (d) Hi, Aman
25. 25.🔁 What number does this code show?
    let scores = [1, 9, 3, 15, 16];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
26. 26.🔁 What number does this code show?
    let marks = [53, 75, 29, 38];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
27. 27.🔁 What number does this code show?
    let runs = [17, 8, 19, 7, 3];
    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 scores = [16, 6, 18, 3, 17];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
29. 29.🔁 What number does this code show?
    let marks = [32, 94, 26];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
30. 30.🔁 What number does this code show?
    let marks = [3, 12, 7, 5, 7];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
31. 31.🔁 What number does this code show?
    let scores = [7, 15, 2];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
32. 32.🔁 What number does this code show?
    let marks = [1, 14, 18];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
33. 33.🔁 A loop over a list of 5 items runs its body how many times? (a) 6 (b) 1 (c) 4 (d) 5
34. 34.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 1, 2, 3 (b) 3 (c) 0, 1, 2 (d) 0, 1, 2, 3
35. 35.🔁 What number does this code show?
    let scores = [4, 12, 9, 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", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Kabir
37. 37.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Zoya", "Riya", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Riya (c) Hi, Arjun (d) Hi, Kabir
38. 38.🔁 What number does this code show?
    let scores = [16, 20, 12, 10];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
39. 39.🔁 What number does this code show?
    let steps = [35, 35, 33];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
40. 40.🔁 What number does this code show?
    let steps = [18, 17, 1, 12, 6];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);

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