App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 12 · 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 = [4, 16, 10, 2];
   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 steps = [71, 86, 80, 33];
   let count = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] >= 70) {
       count = count + 1;
     }
   }
   show(count);
3. 3.🔁 What number does this code show?
   let steps = [2, 20, 8];
   let best = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] > best) {
       best = steps[i];
     }
   }
   show(best);
4. 4.🔁 What number does this code show?
   let runs = [71, 86, 34];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 40) {
       count = count + 1;
     }
   }
   show(count);
5. 5.🔁 What number does this code show?
   let steps = [11, 18, 2, 8];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
6. 6.🔁 What number does this code show?
   let scores = [34, 86, 45, 80];
   let count = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] >= 40) {
       count = count + 1;
     }
   }
   show(count);
7. 7.🔁 What is the LAST line this code shows?
   let names = ["Aman", "Riya", "Zoya", "Arjun"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Arjun (b) Hi, Riya (c) Hi, Aman (d) Hi, Zoya
8. 8.🔁 list.length tells you ___. (a) the last item (b) the biggest item (c) how many items it has (d) the first item
9. 9.🔁 What number does this code show?
   let marks = [90, 84, 23];
   let count = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
10. 10.🔁 What number does this code show?
    let scores = [60, 54, 34];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
11. 11.🔁 What number does this code show?
    let scores = [10, 12, 9];
    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 = [1, 7, 19, 2, 12];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
13. 13.🔁 What does a loop do? (a) draws icons (b) saves photos (c) deletes code (d) repeats code
14. 14.🔁 What number does this code show?
    let marks = [20, 1, 11, 8, 12];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
15. 15.🔁 What number does this code show?
    let steps = [82, 95, 95];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
16. 16.🔁 What number does this code show?
    let runs = [68, 84, 39, 88];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
17. 17.🔁 What number does this code show?
    let scores = [4, 2, 15, 3, 4];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
18. 18.🔁 What number does this code show?
    let runs = [20, 3, 20, 18, 15];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
19. 19.🔁 What number does this code show?
    let scores = [6, 12, 6];
    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 runs = [6, 4, 14, 10];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
21. 21.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Riya", "Zoya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Zoya (c) Hi, Kabir (d) Hi, Riya
22. 22.🔁 What number does this code show?
    let marks = [20, 19, 7];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
23. 23.🔁 What number does this code show?
    let marks = [6, 14, 8];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
24. 24.🔁 What number does this code show?
    let scores = [58, 73, 72, 92];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
25. 25.🔁 What number does this code show?
    let steps = [3, 19, 19];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
26. 26.🔁 What number does this code show?
    let scores = [13, 10, 15];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
27. 27.🔁 What number does this code show?
    let runs = [5, 19, 5, 4];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
28. 28.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 0, 1, 2, 3 (b) 1, 2, 3 (c) 3 (d) 0, 1, 2
29. 29.🔁 What number does this code show?
    let steps = [20, 8, 8, 5, 20];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
30. 30.🔁 What number does this code show?
    let marks = [10, 15, 7];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
31. 31.🔁 What number does this code show?
    let marks = [32, 87, 11, 54];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
32. 32.🔁 Why use a loop to show 100 messages? (a) it is slower (b) less code to write (c) it hides them (d) it uses more lines
33. 33.🔁 What number does this code show?
    let scores = [34, 71, 45, 28];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
34. 34.🔁 What number does this code show?
    let marks = [5, 18, 16, 12];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
35. 35.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Aman (c) Hi, Riya
36. 36.🔁 What number does this code show?
    let steps = [60, 69, 96, 13, 75];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
37. 37.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Arjun", "Zoya", "Aman", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Arjun (c) Hi, Kabir (d) Hi, Zoya
38. 38.🔁 What number does this code show?
    let marks = [53, 90, 24, 60];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
39. 39.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Arjun", "Kabir", "Riya", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Kabir (c) Hi, Arjun (d) Hi, Meera
40. 40.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Meera", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Aman (c) Hi, Riya (d) Hi, Zoya

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