App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 291 · 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 = [19, 11, 3, 18, 5];
   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 steps = [13, 11, 13, 9, 9];
   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, 1, 8, 13];
   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) repeats code (b) deletes code (c) saves photos (d) draws icons
5. 5.🔁 What number does this code show?
   let scores = [12, 11, 16, 7, 9];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
6. 6.🔁 What number does this code show?
   let steps = [20, 4, 16, 12, 9];
   let best = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] > best) {
       best = steps[i];
     }
   }
   show(best);
7. 7.🔁 What is the LAST line this code shows?
   let names = ["Meera", "Kabir", "Arjun", "Aman", "Zoya"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Meera (b) Hi, Arjun (c) Hi, Zoya (d) Hi, Kabir
8. 8.🔁 What number does this code show?
   let scores = [2, 6, 16, 5, 4];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
9. 9.🔁 What number does this code show?
   let scores = [19, 13, 20, 1];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
10. 10.🔁 What number does this code show?
    let runs = [68, 43, 89];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
11. 11.🔁 What number does this code show?
    let marks = [35, 66, 74, 39, 14];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
12. 12.🔁 What number does this code show?
    let marks = [2, 20, 18];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
13. 13.🔁 list.length tells you ___. (a) the first item (b) the biggest item (c) the last item (d) how many items it has
14. 14.🔁 What number does this code show?
    let scores = [13, 17, 2, 5, 5];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
15. 15.🔁 What number does this code show?
    let scores = [20, 16, 4, 19, 8];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
16. 16.🔁 What number does this code show?
    let scores = [9, 4, 12];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
17. 17.🔁 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
18. 18.🔁 What number does this code show?
    let steps = [76, 25, 56];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
19. 19.🔁 What number does this code show?
    let marks = [12, 9, 3];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
20. 20.🔁 Why use a loop to show 100 messages? (a) it hides them (b) it uses more lines (c) it is slower (d) less code to write
21. 21.🔁 What number does this code show?
    let steps = [7, 13, 1];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
22. 22.🔁 A loop over a list of 5 items runs its body how many times? (a) 1 (b) 6 (c) 5 (d) 4
23. 23.🔁 What number does this code show?
    let runs = [7, 2, 9];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
24. 24.🔁 What number does this code show?
    let marks = [8, 6, 4, 17];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
25. 25.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Kabir", "Riya", "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
26. 26.🔁 What number does this code show?
    let scores = [19, 2, 9, 1];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
27. 27.🔁 What number does this code show?
    let scores = [8, 5, 1, 12];
    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 = [19, 12, 4];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
29. 29.🔁 What number does this code show?
    let steps = [5, 11, 20, 4];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
30. 30.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Arjun", "Kabir", "Meera", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Zoya (c) Hi, Arjun (d) Hi, Kabir
31. 31.🔁 What number does this code show?
    let scores = [10, 12, 6, 17];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
32. 32.🔁 What number does this code show?
    let marks = [11, 7, 15, 8, 5];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
33. 33.🔁 What number does this code show?
    let marks = [4, 12, 11];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
34. 34.🔁 What number does this code show?
    let scores = [1, 9, 3];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
35. 35.🔁 What number does this code show?
    let runs = [12, 15, 12, 16];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
36. 36.🔁 What number does this code show?
    let steps = [13, 9, 9, 14];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
37. 37.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Meera", "Arjun", "Aman", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Riya (c) Hi, Kabir (d) Hi, Arjun
38. 38.🔁 What number does this code show?
    let steps = [14, 18, 12, 12];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
39. 39.🔁 What number does this code show?
    let marks = [47, 19, 35, 27, 89];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
40. 40.🔁 What number does this code show?
    let runs = [60, 11, 78, 46, 95];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);

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