App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 142 · 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 = [11, 5, 7];
   let total = 0;
   for (let i = 0; i < runs.length; i++) {
     total = total + runs[i];
   }
   show(total);
2. 2.🔁 What number does this code show?
   let marks = [13, 11, 12, 3];
   let best = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] > best) {
       best = marks[i];
     }
   }
   show(best);
3. 3.🔁 What is the LAST line this code shows?
   let names = ["Zoya", "Aman", "Riya"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Aman (b) Hi, Riya (c) Hi, Zoya
4. 4.🔁 What number does this code show?
   let steps = [9, 5, 14];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
5. 5.🔁 What number does this code show?
   let runs = [2, 7, 4, 6, 2];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
6. 6.🔁 What is the LAST line this code shows?
   let names = ["Riya", "Aman", "Zoya"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Aman (b) Hi, Riya (c) Hi, Zoya
7. 7.🔁 What number does this code show?
   let runs = [5, 15, 12, 9];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
8. 8.🔁 What number does this code show?
   let scores = [9, 2, 19, 14];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
9. 9.🔁 What number does this code show?
   let marks = [18, 14, 12, 4];
   let best = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] > best) {
       best = marks[i];
     }
   }
   show(best);
10. 10.🔁 What number does this code show?
    let steps = [14, 3, 2, 13, 3];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
11. 11.🔁 What does a loop do? (a) saves photos (b) deletes code (c) draws icons (d) repeats code
12. 12.🔁 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
13. 13.🔁 What number does this code show?
    let steps = [5, 20, 11, 11, 11];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
14. 14.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Zoya", "Aman", "Kabir", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Zoya (c) Hi, Riya (d) Hi, Aman
15. 15.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Aman", "Zoya", "Arjun", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Riya (c) Hi, Aman (d) Hi, Meera
16. 16.🔁 What number does this code show?
    let marks = [9, 10, 18];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
17. 17.🔁 What number does this code show?
    let steps = [41, 59, 46, 57, 46];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
18. 18.🔁 list.length tells you ___. (a) the biggest item (b) how many items it has (c) the last item (d) the first item
19. 19.🔁 What number does this code show?
    let steps = [27, 16, 21, 46, 72];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
20. 20.🔁 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
21. 21.🔁 What number does this code show?
    let scores = [38, 55, 69, 82, 26];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
22. 22.🔁 What number does this code show?
    let runs = [7, 6, 6, 9];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
23. 23.🔁 What number does this code show?
    let marks = [32, 94, 21, 47, 71];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
24. 24.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Meera (c) Hi, Kabir (d) Hi, Arjun
25. 25.🔁 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
26. 26.🔁 A loop over a list of 5 items runs its body how many times? (a) 5 (b) 6 (c) 4 (d) 1
27. 27.🔁 What number does this code show?
    let scores = [24, 51, 32, 99, 57];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
28. 28.🔁 What number does this code show?
    let runs = [11, 19, 14];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
29. 29.🔁 What number does this code show?
    let steps = [32, 57, 48];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
30. 30.🔁 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, Riya (b) Hi, Meera (c) Hi, Arjun
31. 31.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Riya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Riya (c) Hi, Arjun (d) Hi, Kabir
32. 32.🔁 What number does this code show?
    let scores = [59, 92, 51, 81];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 60) {
        count = count + 1;
      }
    }
    show(count);
33. 33.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Arjun", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Zoya (c) Hi, Arjun
34. 34.🔁 What number does this code show?
    let runs = [29, 99, 94, 17, 42];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
35. 35.🔁 What number does this code show?
    let scores = [7, 6, 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 steps = [1, 1, 9, 15];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
37. 37.🔁 What number does this code show?
    let steps = [12, 16, 4, 10, 15];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
38. 38.🔁 What number does this code show?
    let scores = [3, 2, 7, 2, 11];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);
39. 39.🔁 What number does this code show?
    let steps = [9, 1, 11];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
40. 40.🔁 What number does this code show?
    let scores = [17, 5, 1];
    let best = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] > best) {
        best = scores[i];
      }
    }
    show(best);

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