App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 356 · 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 runs = [59, 91, 33];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 40) {
       count = count + 1;
     }
   }
   show(count);
2. 2.🔁 What number does this code show?
   let runs = [6, 9, 20, 1];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
3. 3.🔁 What number does this code show?
   let scores = [15, 15, 14, 1];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
4. 4.🔁 What number does this code show?
   let steps = [18, 4, 20, 14, 6];
   let best = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] > best) {
       best = steps[i];
     }
   }
   show(best);
5. 5.🔁 What is the LAST line this code shows?
   let names = ["Zoya", "Kabir", "Arjun", "Meera", "Aman"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Aman (b) Hi, Arjun (c) Hi, Zoya (d) Hi, Kabir
6. 6.🔁 What number does this code show?
   let scores = [19, 48, 61];
   let count = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] >= 40) {
       count = count + 1;
     }
   }
   show(count);
7. 7.🔁 What number does this code show?
   let runs = [7, 11, 4, 8];
   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 steps = [5, 17, 11];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
9. 9.🔁 What does a loop do? (a) repeats code (b) saves photos (c) deletes code (d) draws icons
10. 10.🔁 What number does this code show?
    let scores = [16, 18, 4];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
11. 11.🔁 What number does this code show?
    let scores = [13, 96, 28];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
12. 12.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 3 (b) 0, 1, 2, 3 (c) 1, 2, 3 (d) 0, 1, 2
13. 13.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Meera", "Kabir", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Meera (c) Hi, Aman (d) Hi, Arjun
14. 14.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Riya", "Meera", "Kabir", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Riya (c) Hi, Meera (d) Hi, Arjun
15. 15.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 1 (c) 6 (d) 5
16. 16.🔁 What number does this code show?
    let steps = [63, 24, 44];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
17. 17.🔁 What number does this code show?
    let runs = [23, 65, 56, 32];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
18. 18.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Meera", "Aman", "Riya", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Zoya (c) Hi, Aman (d) Hi, Kabir
19. 19.🔁 What number does this code show?
    let steps = [5, 2, 16];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
20. 20.🔁 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
21. 21.🔁 What number does this code show?
    let runs = [8, 2, 4, 14, 16];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
22. 22.🔁 What number does this code show?
    let runs = [87, 99, 87, 62, 52];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
23. 23.🔁 What number does this code show?
    let scores = [93, 62, 23, 50, 55];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
24. 24.🔁 What number does this code show?
    let scores = [32, 85, 10];
    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 runs = [93, 21, 47, 58];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
26. 26.🔁 What number does this code show?
    let runs = [17, 1, 11, 9, 14];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
27. 27.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Zoya (c) Hi, Arjun
28. 28.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Aman", "Zoya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Zoya (c) Hi, Aman (d) Hi, Kabir
29. 29.🔁 What number does this code show?
    let runs = [9, 14, 4, 20];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
30. 30.🔁 What number does this code show?
    let marks = [4, 20, 11, 2, 3];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
31. 31.🔁 What number does this code show?
    let runs = [5, 15, 18, 16, 12];
    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 marks = [96, 34, 11];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
33. 33.🔁 What number does this code show?
    let scores = [19, 3, 16];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
34. 34.🔁 What number does this code show?
    let runs = [8, 3, 5];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
35. 35.🔁 What number does this code show?
    let marks = [2, 6, 9];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
36. 36.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Aman", "Riya", "Kabir", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Zoya (c) Hi, Riya (d) Hi, Arjun
37. 37.🔁 What number does this code show?
    let steps = [62, 78, 50];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
38. 38.🔁 What number does this code show?
    let scores = [15, 11, 3, 8];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
39. 39.🔁 list.length tells you ___. (a) how many items it has (b) the biggest item (c) the last item (d) the first item
40. 40.🔁 What number does this code show?
    let runs = [13, 6, 1, 14, 6];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);

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