App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 773 · 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 = [78, 11, 17];
   let count = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
2. 2.🔁 What number does this code show?
   let steps = [7, 20, 7, 11, 16];
   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 marks = [2, 2, 19, 9, 15];
   let best = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] > best) {
       best = marks[i];
     }
   }
   show(best);
4. 4.🔁 What number does this code show?
   let steps = [35, 16, 20];
   let count = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
5. 5.🔁 What number does this code show?
   let marks = [10, 19, 19];
   let best = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] > best) {
       best = marks[i];
     }
   }
   show(best);
6. 6.🔁 What number does this code show?
   let runs = [19, 2, 4, 6];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
7. 7.🔁 What number does this code show?
   let steps = [1, 19, 1, 7];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
8. 8.🔁 What is the LAST line this code shows?
   let names = ["Arjun", "Aman", "Riya", "Meera"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Aman (b) Hi, Riya (c) Hi, Meera (d) Hi, Arjun
9. 9.🔁 What is the LAST line this code shows?
   let names = ["Zoya", "Aman", "Arjun", "Meera"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Arjun (b) Hi, Aman (c) Hi, Zoya (d) Hi, Meera
10. 10.🔁 What does a loop do? (a) saves photos (b) deletes code (c) repeats code (d) draws icons
11. 11.🔁 What number does this code show?
    let scores = [19, 18, 11];
    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 scores = [6, 15, 10];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
13. 13.🔁 What number does this code show?
    let scores = [11, 17, 12, 18];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
14. 14.🔁 What number does this code show?
    let runs = [14, 1, 2, 10, 10];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
15. 15.🔁 What number does this code show?
    let marks = [46, 35, 39, 38];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
16. 16.🔁 What number does this code show?
    let steps = [1, 10, 5, 2];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
17. 17.🔁 What number does this code show?
    let runs = [17, 12, 7];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
18. 18.🔁 A loop over a list of 5 items runs its body how many times? (a) 1 (b) 6 (c) 4 (d) 5
19. 19.🔁 What number does this code show?
    let runs = [28, 49, 57];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
20. 20.🔁 list.length tells you ___. (a) the last item (b) the biggest item (c) the first item (d) how many items it has
21. 21.🔁 What number does this code show?
    let runs = [10, 3, 4];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
22. 22.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Meera", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Meera (c) Hi, Aman (d) Hi, Zoya
23. 23.🔁 What number does this code show?
    let runs = [5, 4, 1, 1, 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 scores = [14, 5, 16, 15];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
25. 25.🔁 What number does this code show?
    let steps = [7, 15, 8];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
26. 26.🔁 What number does this code show?
    let scores = [1, 1, 19];
    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 marks = [2, 12, 6];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
28. 28.🔁 What number does this code show?
    let steps = [1, 5, 13, 7];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
29. 29.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Riya", "Zoya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Riya (c) Hi, Arjun (d) Hi, Zoya
30. 30.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Zoya (c) Hi, Arjun
31. 31.🔁 Why use a loop to show 100 messages? (a) it is slower (b) it uses more lines (c) less code to write (d) it hides them
32. 32.🔁 What number does this code show?
    let scores = [31, 26, 22, 15, 22];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
33. 33.🔁 What number does this code show?
    let marks = [99, 58, 94];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
34. 34.🔁 What number does this code show?
    let marks = [3, 7, 3, 10];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
35. 35.🔁 What number does this code show?
    let scores = [16, 15, 17, 3, 10];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
36. 36.🔁 What number does this code show?
    let marks = [6, 19, 3, 3, 6];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
37. 37.🔁 What number does this code show?
    let steps = [9, 18, 4, 3];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
38. 38.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 1, 2, 3 (b) 0, 1, 2, 3 (c) 0, 1, 2 (d) 3
39. 39.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Riya", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Aman (c) Hi, Meera
40. 40.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Kabir", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Zoya (c) Hi, Kabir

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