App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 477 · 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.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2 (b) 1, 2, 3 (c) 3 (d) 0, 1, 2, 3
2. 2.🔁 list.length tells you ___. (a) the biggest item (b) the first item (c) the last item (d) how many items it has
3. 3.🔁 What number does this code show?
   let runs = [7, 12, 16];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
4. 4.🔁 What number does this code show?
   let scores = [31, 23, 86];
   let count = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
5. 5.🔁 What number does this code show?
   let scores = [9, 5, 11, 13];
   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 = [6, 5, 3];
   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 = [10, 14, 9, 6, 19];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
8. 8.🔁 What number does this code show?
   let runs = [2, 4, 20];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
9. 9.🔁 What number does this code show?
   let scores = [13, 2, 3, 3, 20];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
10. 10.🔁 What does a loop do? (a) repeats code (b) saves photos (c) deletes code (d) draws icons
11. 11.🔁 What number does this code show?
    let scores = [6, 12, 8, 14, 16];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
12. 12.🔁 What number does this code show?
    let marks = [8, 10, 8];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
13. 13.🔁 What number does this code show?
    let runs = [7, 3, 12];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
14. 14.🔁 What number does this code show?
    let scores = [14, 1, 4, 3];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
15. 15.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Kabir", "Zoya", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Zoya (c) Hi, Meera (d) Hi, Kabir
16. 16.🔁 What number does this code show?
    let scores = [12, 5, 3, 5];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
17. 17.🔁 What number does this code show?
    let steps = [17, 4, 19];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
18. 18.🔁 What number does this code show?
    let scores = [2, 5, 16, 3, 6];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
19. 19.🔁 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, Kabir (c) Hi, Zoya
20. 20.🔁 What number does this code show?
    let runs = [19, 40, 24, 55, 75];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
21. 21.🔁 What number does this code show?
    let scores = [82, 19, 58];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
22. 22.🔁 What number does this code show?
    let runs = [6, 6, 7];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
23. 23.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Meera", "Aman", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Meera (c) Hi, Aman (d) Hi, Kabir
24. 24.🔁 Why use a loop to show 100 messages? (a) it uses more lines (b) it is slower (c) it hides them (d) less code to write
25. 25.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Aman", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Aman (c) Hi, Kabir (d) Hi, Arjun
26. 26.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Zoya", "Aman", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Meera (c) Hi, Zoya (d) Hi, Kabir
27. 27.🔁 What number does this code show?
    let scores = [96, 31, 64, 82, 17];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
28. 28.🔁 What number does this code show?
    let marks = [49, 37, 17, 45];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
29. 29.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Aman", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Riya (d) Hi, Aman
30. 30.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Zoya", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Meera (c) Hi, Zoya (d) Hi, Arjun
31. 31.🔁 What number does this code show?
    let runs = [16, 1, 18, 18, 16];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
32. 32.🔁 What number does this code show?
    let steps = [22, 24, 35, 31];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
33. 33.🔁 What number does this code show?
    let runs = [16, 20, 12, 8, 9];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
34. 34.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Aman", "Kabir", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Kabir (c) Hi, Arjun (d) Hi, Aman
35. 35.🔁 What number does this code show?
    let steps = [8, 12, 12];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
36. 36.🔁 What number does this code show?
    let marks = [1, 19, 8, 16];
    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 scores = [1, 7, 6, 5];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
38. 38.🔁 What number does this code show?
    let steps = [7, 6, 1];
    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 scores = [1, 4, 16, 7];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
40. 40.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Meera

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