App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 934 · 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 is the LAST line this code shows?
   let names = ["Riya", "Aman", "Meera"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Meera (b) Hi, Riya (c) Hi, Aman
2. 2.🔁 What number does this code show?
   let scores = [22, 44, 58];
   let count = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
3. 3.🔁 What number does this code show?
   let scores = [82, 42, 72];
   let count = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
4. 4.🔁 What number does this code show?
   let runs = [17, 15, 7, 2];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
5. 5.🔁 What number does this code show?
   let runs = [6, 10, 5, 2, 9];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
6. 6.🔁 What number does this code show?
   let runs = [11, 3, 4, 20];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
7. 7.🔁 A loop over a list of 5 items runs its body how many times? (a) 5 (b) 6 (c) 1 (d) 4
8. 8.🔁 What number does this code show?
   let runs = [60, 18, 93, 12, 34];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 40) {
       count = count + 1;
     }
   }
   show(count);
9. 9.🔁 What number does this code show?
   let runs = [48, 14, 56, 68, 19];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
10. 10.🔁 What number does this code show?
    let runs = [8, 6, 6, 15, 14];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
11. 11.🔁 What number does this code show?
    let runs = [43, 35, 13, 27];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
12. 12.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Zoya (c) Hi, Arjun (d) Hi, Riya
13. 13.🔁 What number does this code show?
    let steps = [18, 7, 1, 3, 4];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
14. 14.🔁 What number does this code show?
    let marks = [73, 62, 74, 53];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
15. 15.🔁 What number does this code show?
    let runs = [19, 13, 3, 6];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
16. 16.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Arjun", "Riya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Arjun (c) Hi, Zoya (d) Hi, Kabir
17. 17.🔁 What number does this code show?
    let marks = [15, 20, 18];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
18. 18.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Zoya (c) Hi, Arjun
19. 19.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Meera", "Riya", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Aman (c) Hi, Riya (d) Hi, Meera
20. 20.🔁 What number does this code show?
    let steps = [17, 1, 13, 8, 2];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
21. 21.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Kabir", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Kabir (c) Hi, Riya
22. 22.🔁 What number does this code show?
    let runs = [9, 14, 15, 18];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
23. 23.🔁 What number does this code show?
    let runs = [2, 9, 18, 1, 10];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
24. 24.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Meera", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Aman (c) Hi, Meera
25. 25.🔁 What does a loop do? (a) deletes code (b) repeats code (c) draws icons (d) saves photos
26. 26.🔁 What number does this code show?
    let scores = [67, 38, 59];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
27. 27.🔁 What number does this code show?
    let runs = [14, 13, 5, 5, 17];
    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) 3 (c) 0, 1, 2 (d) 1, 2, 3
29. 29.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Arjun (c) Hi, Riya
30. 30.🔁 What number does this code show?
    let steps = [46, 78, 92, 59];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
31. 31.🔁 list.length tells you ___. (a) the first item (b) the last item (c) the biggest item (d) how many items it has
32. 32.🔁 What number does this code show?
    let scores = [46, 14, 75, 75, 81];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
33. 33.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Kabir", "Meera"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Meera (c) Hi, Aman
34. 34.🔁 What number does this code show?
    let marks = [9, 4, 5];
    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 steps = [22, 25, 25, 18, 97];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
36. 36.🔁 What number does this code show?
    let runs = [9, 2, 13, 18];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
37. 37.🔁 What number does this code show?
    let marks = [19, 20, 18];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
38. 38.🔁 What number does this code show?
    let scores = [9, 15, 2, 4, 16];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
39. 39.🔁 Why use a loop to show 100 messages? (a) it uses more lines (b) less code to write (c) it is slower (d) it hides them
40. 40.🔁 What number does this code show?
    let marks = [3, 16, 17, 11];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);

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