App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 425 · 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 = [14, 11, 7];
   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", "Aman", "Zoya"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Meera (b) Hi, Zoya (c) Hi, Aman
3. 3.🔁 What is the LAST line this code shows?
   let names = ["Riya", "Aman", "Arjun", "Kabir"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Aman (b) Hi, Arjun (c) Hi, Riya (d) Hi, Kabir
4. 4.🔁 Why use a loop to show 100 messages? (a) it is slower (b) it uses more lines (c) it hides them (d) less code to write
5. 5.🔁 list.length tells you ___. (a) the last item (b) the biggest item (c) how many items it has (d) the first item
6. 6.🔁 What is the LAST line this code shows?
   let names = ["Riya", "Kabir", "Meera"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Meera (b) Hi, Kabir (c) Hi, Riya
7. 7.🔁 What number does this code show?
   let steps = [20, 8, 13, 15, 13];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
8. 8.🔁 What number does this code show?
   let marks = [6, 6, 3, 13];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
9. 9.🔁 What does a loop do? (a) saves photos (b) draws icons (c) deletes code (d) repeats code
10. 10.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 1 (c) 6 (d) 5
11. 11.🔁 What number does this code show?
    let scores = [14, 1, 17, 14];
    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 steps = [33, 80, 72];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
13. 13.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Meera", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Meera (d) Hi, Riya
14. 14.🔁 What number does this code show?
    let scores = [19, 17, 12];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
15. 15.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 1, 2, 3 (b) 0, 1, 2, 3 (c) 3 (d) 0, 1, 2
16. 16.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Meera (c) Hi, Riya
17. 17.🔁 What number does this code show?
    let runs = [33, 23, 31];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
18. 18.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Arjun", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Arjun (c) Hi, Zoya
19. 19.🔁 What number does this code show?
    let scores = [4, 19, 16, 2, 18];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
20. 20.🔁 What number does this code show?
    let steps = [45, 84, 71, 22, 88];
    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 = ["Arjun", "Kabir", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Kabir (c) Hi, Riya
22. 22.🔁 What number does this code show?
    let runs = [2, 13, 12, 5, 2];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
23. 23.🔁 What number does this code show?
    let steps = [4, 3, 4];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
24. 24.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Aman", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Kabir (c) Hi, Riya
25. 25.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Kabir", "Meera", "Aman", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Meera (c) Hi, Riya (d) Hi, Kabir
26. 26.🔁 What number does this code show?
    let scores = [87, 71, 56, 51, 77];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
27. 27.🔁 What number does this code show?
    let scores = [82, 84, 31];
    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 = [66, 92, 72, 60];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
29. 29.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Meera (c) Hi, Zoya
30. 30.🔁 What number does this code show?
    let marks = [90, 12, 33];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
31. 31.🔁 What number does this code show?
    let runs = [4, 17, 5, 3];
    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 marks = [1, 20, 17, 11];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
33. 33.🔁 What number does this code show?
    let steps = [12, 96, 70];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
34. 34.🔁 What number does this code show?
    let steps = [80, 10, 28];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
35. 35.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Zoya", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Riya (c) Hi, Arjun (d) Hi, Aman
36. 36.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Aman", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Zoya (c) Hi, Meera (d) Hi, Riya
37. 37.🔁 What number does this code show?
    let scores = [5, 2, 8, 3, 7];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
38. 38.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Kabir", "Zoya", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Meera (c) Hi, Zoya (d) Hi, Arjun
39. 39.🔁 What number does this code show?
    let runs = [6, 14, 11, 20, 13];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
40. 40.🔁 What number does this code show?
    let scores = [40, 71, 86];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);

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