App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 283 · 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 = [44, 70, 21];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 70) {
       count = count + 1;
     }
   }
   show(count);
2. 2.🔁 What is the LAST line this code shows?
   let names = ["Riya", "Meera", "Zoya", "Arjun", "Kabir"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Zoya (b) Hi, Kabir (c) Hi, Meera (d) Hi, Riya
3. 3.🔁 What number does this code show?
   let scores = [17, 17, 16];
   let total = 0;
   for (let i = 0; i < scores.length; i++) {
     total = total + scores[i];
   }
   show(total);
4. 4.🔁 What is the LAST line this code shows?
   let names = ["Aman", "Arjun", "Riya", "Zoya", "Meera"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Riya (b) Hi, Meera (c) Hi, Aman (d) Hi, Arjun
5. 5.🔁 What number does this code show?
   let runs = [2, 16, 2];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
6. 6.🔁 What number does this code show?
   let steps = [5, 1, 10, 10];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
7. 7.🔁 What number does this code show?
   let marks = [11, 5, 2];
   let total = 0;
   for (let i = 0; i < marks.length; i++) {
     total = total + marks[i];
   }
   show(total);
8. 8.🔁 What number does this code show?
   let steps = [66, 64, 24, 66];
   let count = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
9. 9.🔁 What is the LAST line this code shows?
   let names = ["Aman", "Arjun", "Meera"];
   for (let i = 0; i < names.length; i++) {
     show("Hi, " + names[i]);
   } (a) Hi, Arjun (b) Hi, Meera (c) Hi, Aman
10. 10.🔁 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, Zoya (b) Hi, Aman (c) Hi, Arjun
11. 11.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Aman", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Riya (c) Hi, Aman (d) Hi, Arjun
12. 12.🔁 What number does this code show?
    let runs = [81, 72, 39, 70, 96];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
13. 13.🔁 What number does this code show?
    let steps = [5, 18, 7, 17, 3];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
14. 14.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Aman", "Riya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Riya (c) Hi, Kabir (d) Hi, Aman
15. 15.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Arjun", "Riya", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Meera (d) Hi, Riya
16. 16.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Kabir", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Kabir (c) Hi, Aman
17. 17.🔁 list.length tells you ___. (a) the first item (b) the biggest item (c) the last item (d) how many items it has
18. 18.🔁 What number does this code show?
    let steps = [18, 2, 4, 7];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
19. 19.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Aman (c) Hi, Zoya
20. 20.🔁 A loop over a list of 5 items runs its body how many times? (a) 1 (b) 6 (c) 5 (d) 4
21. 21.🔁 What number does this code show?
    let steps = [1, 14, 4, 9];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
22. 22.🔁 What number does this code show?
    let scores = [45, 96, 37, 37, 69];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
23. 23.🔁 What number does this code show?
    let marks = [11, 6, 11, 19, 10];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
24. 24.🔁 What number does this code show?
    let marks = [15, 4, 6, 4, 17];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
25. 25.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Kabir", "Zoya", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Kabir (c) Hi, Zoya (d) Hi, Arjun
26. 26.🔁 What number does this code show?
    let steps = [14, 3, 16, 10, 7];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
27. 27.🔁 What is the LAST line this code shows?
    let names = ["Arjun", "Meera", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Meera (c) Hi, Kabir
28. 28.🔁 What number does this code show?
    let scores = [20, 3, 18];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
29. 29.🔁 What number does this code show?
    let runs = [14, 2, 16];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
30. 30.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Meera (b) Hi, Riya (c) Hi, Arjun
31. 31.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Riya", "Zoya", "Arjun", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Riya (c) Hi, Kabir (d) Hi, Meera
32. 32.🔁 What number does this code show?
    let steps = [4, 10, 1];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
33. 33.🔁 What number does this code show?
    let scores = [29, 46, 11, 32, 33];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
34. 34.🔁 What number does this code show?
    let runs = [19, 9, 10, 10, 2];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
35. 35.🔁 What number does this code show?
    let marks = [17, 14, 1];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
36. 36.🔁 Why use a loop to show 100 messages? (a) less code to write (b) it hides them (c) it is slower (d) it uses more lines
37. 37.🔁 What number does this code show?
    let marks = [70, 51, 86];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
38. 38.🔁 What number does this code show?
    let steps = [19, 12, 3];
    let best = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] > best) {
        best = steps[i];
      }
    }
    show(best);
39. 39.🔁 What number does this code show?
    let marks = [4, 6, 9, 2];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
40. 40.🔁 What number does this code show?
    let steps = [38, 31, 79];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);

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