App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 438 · 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 is the LAST line this code shows?
   let names = ["Zoya", "Riya", "Kabir"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Kabir (b) Hi, Zoya (c) Hi, Riya
2. 2.🔁 What number does this code show?
   let steps = [5, 16, 19];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
3. 3.🔁 What number does this code show?
   let scores = [3, 20, 7];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
4. 4.🔁 What number does this code show?
   let scores = [1, 20, 8, 20];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
5. 5.🔁 What number does this code show?
   let steps = [15, 13, 11];
   let best = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] > best) {
       best = steps[i];
     }
   }
   show(best);
6. 6.🔁 What number does this code show?
   let runs = [11, 18, 8, 6];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
7. 7.🔁 What number does this code show?
   let runs = [8, 7, 1, 3, 10];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
8. 8.🔁 list.length tells you ___. (a) the biggest item (b) the last item (c) the first item (d) how many items it has
9. 9.🔁 What does a loop do? (a) draws icons (b) repeats code (c) saves photos (d) deletes code
10. 10.🔁 What number does this code show?
    let steps = [14, 9, 1, 17, 15];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
11. 11.🔁 What number does this code show?
    let scores = [13, 2, 2, 20];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
12. 12.🔁 What number does this code show?
    let runs = [13, 18, 3, 2, 17];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
13. 13.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Zoya", "Kabir", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Kabir (c) Hi, Arjun (d) Hi, Meera
14. 14.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Kabir", "Arjun", "Aman", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Kabir (c) Hi, Arjun (d) Hi, Meera
15. 15.🔁 What number does this code show?
    let steps = [6, 13, 16, 14];
    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 = ["Riya", "Kabir", "Arjun", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Kabir (c) Hi, Arjun (d) Hi, Aman
17. 17.🔁 What number does this code show?
    let scores = [21, 56, 31, 44, 70];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
18. 18.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Zoya", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Riya (c) Hi, Aman (d) Hi, Zoya
19. 19.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Riya (c) Hi, Meera
20. 20.🔁 What number does this code show?
    let scores = [29, 52, 17, 98];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
21. 21.🔁 What number does this code show?
    let runs = [24, 54, 42, 36, 50];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
22. 22.🔁 What number does this code show?
    let steps = [20, 17, 17];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
23. 23.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Riya (c) Hi, Arjun
24. 24.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Meera", "Aman", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Aman (c) Hi, Riya (d) Hi, Meera
25. 25.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Aman", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Zoya (c) Hi, Aman
26. 26.🔁 What number does this code show?
    let scores = [7, 7, 10];
    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, 15, 2];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
28. 28.🔁 What number does this code show?
    let scores = [19, 19, 4, 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 = [51, 86, 10];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
30. 30.🔁 What number does this code show?
    let steps = [3, 17, 10, 12, 11];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
31. 31.🔁 What number does this code show?
    let marks = [13, 6, 16];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
32. 32.🔁 Why use a loop to show 100 messages? (a) it hides them (b) less code to write (c) it uses more lines (d) it is slower
33. 33.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Kabir", "Zoya", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Kabir (c) Hi, Zoya (d) Hi, Aman
34. 34.🔁 What number does this code show?
    let scores = [14, 1, 14, 9, 19];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
35. 35.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 6 (c) 1 (d) 5
36. 36.🔁 What number does this code show?
    let runs = [96, 75, 24, 83, 25];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
37. 37.🔁 What number does this code show?
    let scores = [13, 20, 16, 12, 17];
    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 scores = [6, 15, 12, 13];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
39. 39.🔁 What number does this code show?
    let runs = [11, 16, 19, 2];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
40. 40.🔁 What number does this code show?
    let runs = [43, 25, 89, 49];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);

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