App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 751 · 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 marks = [20, 11, 7, 14];
   let best = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] > best) {
       best = marks[i];
     }
   }
   show(best);
2. 2.🔁 What number does this code show?
   let runs = [10, 19, 6, 2, 18];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
3. 3.🔁 What number does this code show?
   let marks = [19, 14, 5, 2];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
4. 4.🔁 What is the LAST line this code shows?
   let names = ["Riya", "Zoya", "Kabir"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Zoya (b) Hi, Kabir (c) Hi, Riya
5. 5.🔁 What number does this code show?
   let marks = [20, 1, 16];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
6. 6.🔁 Why use a loop to show 100 messages? (a) less code to write (b) it is slower (c) it uses more lines (d) it hides them
7. 7.🔁 What number does this code show?
   let marks = [40, 18, 66];
   let count = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
8. 8.🔁 What number does this code show?
   let marks = [4, 7, 7, 19];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
9. 9.🔁 What is the LAST line this code shows?
   let names = ["Riya", "Arjun", "Meera"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Arjun (b) Hi, Meera (c) Hi, Riya
10. 10.🔁 What number does this code show?
    let scores = [44, 99, 56];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
11. 11.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Riya", "Arjun", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Meera (d) Hi, Riya
12. 12.🔁 What number does this code show?
    let steps = [53, 69, 20, 75, 76];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
13. 13.🔁 What number does this code show?
    let runs = [11, 18, 10, 4];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
14. 14.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Zoya", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Aman (c) Hi, Zoya (d) Hi, Arjun
15. 15.🔁 What number does this code show?
    let steps = [16, 14, 5];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
16. 16.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 3 (b) 0, 1, 2 (c) 0, 1, 2, 3 (d) 1, 2, 3
17. 17.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Kabir", "Zoya", "Meera", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Arjun (c) Hi, Aman (d) Hi, Zoya
18. 18.🔁 What number does this code show?
    let steps = [6, 20, 9, 18, 6];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
19. 19.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Zoya", "Kabir", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Aman (c) Hi, Riya (d) Hi, Zoya
20. 20.🔁 What number does this code show?
    let steps = [6, 4, 13, 6, 12];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
21. 21.🔁 What number does this code show?
    let scores = [10, 15, 1];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
22. 22.🔁 What number does this code show?
    let scores = [50, 33, 12];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
23. 23.🔁 What number does this code show?
    let runs = [20, 5, 17, 6, 2];
    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 runs = [16, 3, 14, 2];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
25. 25.🔁 What number does this code show?
    let scores = [66, 88, 74, 68, 33];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
26. 26.🔁 What number does this code show?
    let runs = [16, 7, 15, 1];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
27. 27.🔁 What number does this code show?
    let steps = [97, 92, 29, 81, 85];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
28. 28.🔁 What does a loop do? (a) draws icons (b) deletes code (c) saves photos (d) repeats code
29. 29.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Arjun", "Aman", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Arjun (c) Hi, Aman (d) Hi, Zoya
30. 30.🔁 What number does this code show?
    let scores = [3, 4, 2];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
31. 31.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Riya", "Kabir", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Arjun (c) Hi, Riya (d) Hi, Kabir
32. 32.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Aman", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Kabir (c) Hi, Meera (d) Hi, Riya
33. 33.🔁 What number does this code show?
    let scores = [90, 99, 57, 29];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
34. 34.🔁 What number does this code show?
    let scores = [19, 18, 13, 7, 14];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
35. 35.🔁 What number does this code show?
    let scores = [8, 12, 15, 13];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
36. 36.🔁 A loop over a list of 5 items runs its body how many times? (a) 1 (b) 5 (c) 4 (d) 6
37. 37.🔁 What number does this code show?
    let scores = [10, 75, 55, 44, 87];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
38. 38.🔁 What number does this code show?
    let scores = [1, 20, 6, 13];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
39. 39.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Riya", "Meera", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Riya (c) Hi, Meera (d) Hi, Arjun
40. 40.🔁 What number does this code show?
    let scores = [8, 10, 6, 2, 17];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);

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