App Dev Worksheet: Loops over Lists

App development lesson 19: Loops over lists · Set 671 · 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.🔁 A loop over a list of 5 items runs its body how many times? (a) 4 (b) 1 (c) 5 (d) 6
2. 2.🔁 What number does this code show?
   let runs = [94, 77, 58];
   let count = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
3. 3.🔁 What number does this code show?
   let steps = [9, 20, 1, 15, 6];
   let total = 0;
   for (let i = 0; i < steps.length; i++) {
     total = total + steps[i];
   }
   show(total);
4. 4.🔁 What number does this code show?
   let scores = [13, 13, 17, 9];
   let best = 0;
   for (let i = 0; i < scores.length; i++) {
     if (scores[i] > best) {
       best = scores[i];
     }
   }
   show(best);
5. 5.🔁 What number does this code show?
   let marks = [93, 62, 15];
   let count = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] >= 50) {
       count = count + 1;
     }
   }
   show(count);
6. 6.🔁 Why use a loop to show 100 messages? (a) less code to write (b) it uses more lines (c) it is slower (d) it hides them
7. 7.🔁 What number does this code show?
   let marks = [5, 13, 5, 19, 14];
   let best = 0;
   for (let i = 0; i < marks.length; i++) {
     if (marks[i] > best) {
       best = marks[i];
     }
   }
   show(best);
8. 8.🔁 What number does this code show?
   let steps = [97, 61, 40];
   let count = 0;
   for (let i = 0; i < steps.length; i++) {
     if (steps[i] >= 60) {
       count = count + 1;
     }
   }
   show(count);
9. 9.🔁 What number does this code show?
   let runs = [2, 16, 6, 9, 11];
   let best = 0;
   for (let i = 0; i < runs.length; i++) {
     if (runs[i] > best) {
       best = runs[i];
     }
   }
   show(best);
10. 10.🔁 What number does this code show?
    let scores = [55, 39, 24];
    let count = 0;
    for (let i = 0; i < scores.length; i++) {
      if (scores[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
11. 11.🔁 What does a loop do? (a) draws icons (b) deletes code (c) repeats code (d) saves photos
12. 12.🔁 What number does this code show?
    let runs = [7, 19, 2, 19];
    let total = 0;
    for (let i = 0; i < runs.length; i++) {
      total = total + runs[i];
    }
    show(total);
13. 13.🔁 In for (let i = 0; i < 3; i++), which values does i take? (a) 1, 2, 3 (b) 0, 1, 2, 3 (c) 3 (d) 0, 1, 2
14. 14.🔁 What is the LAST line this code shows?
    let names = ["Kabir", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Kabir (b) Hi, Riya (c) Hi, Arjun
15. 15.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Aman", "Zoya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Aman (c) Hi, Riya (d) Hi, Arjun
16. 16.🔁 What number does this code show?
    let marks = [43, 89, 21];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
17. 17.🔁 What number does this code show?
    let steps = [7, 10, 8, 19];
    let total = 0;
    for (let i = 0; i < steps.length; i++) {
      total = total + steps[i];
    }
    show(total);
18. 18.🔁 What is the LAST line this code shows?
    let names = ["Zoya", "Aman", "Arjun", "Riya", "Kabir"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Kabir (c) Hi, Arjun (d) Hi, Aman
19. 19.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Meera", "Zoya", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Meera (c) Hi, Riya (d) Hi, Aman
20. 20.🔁 What number does this code show?
    let runs = [27, 82, 26, 12, 56];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
21. 21.🔁 What number does this code show?
    let marks = [20, 18, 16];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
22. 22.🔁 What number does this code show?
    let marks = [13, 4, 15];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
23. 23.🔁 What number does this code show?
    let scores = [2, 17, 14];
    let total = 0;
    for (let i = 0; i < scores.length; i++) {
      total = total + scores[i];
    }
    show(total);
24. 24.🔁 What number does this code show?
    let runs = [10, 10, 20, 5];
    let best = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] > best) {
        best = runs[i];
      }
    }
    show(best);
25. 25.🔁 What number does this code show?
    let steps = [11, 75, 23, 33];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
26. 26.🔁 What is the LAST line this code shows?
    let names = ["Riya", "Meera", "Zoya", "Kabir", "Aman"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Riya (b) Hi, Zoya (c) Hi, Aman (d) Hi, Meera
27. 27.🔁 What number does this code show?
    let marks = [2, 12, 19];
    let best = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] > best) {
        best = marks[i];
      }
    }
    show(best);
28. 28.🔁 What is the LAST line this code shows?
    let names = ["Meera", "Arjun", "Zoya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Arjun (b) Hi, Zoya (c) Hi, Meera
29. 29.🔁 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, Kabir (c) Hi, Riya (d) Hi, Arjun
30. 30.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Aman (b) Hi, Riya (c) Hi, Arjun
31. 31.🔁 What number does this code show?
    let runs = [61, 56, 27];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 70) {
        count = count + 1;
      }
    }
    show(count);
32. 32.🔁 What number does this code show?
    let marks = [30, 68, 18, 36, 81];
    let count = 0;
    for (let i = 0; i < marks.length; i++) {
      if (marks[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);
33. 33.🔁 What number does this code show?
    let marks = [19, 11, 10, 20, 16];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
34. 34.🔁 What number does this code show?
    let runs = [54, 38, 90, 88, 77];
    let count = 0;
    for (let i = 0; i < runs.length; i++) {
      if (runs[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
35. 35.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Riya", "Arjun"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Riya (c) Hi, Aman (d) Hi, Arjun
36. 36.🔁 What number does this code show?
    let steps = [53, 61, 48];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 50) {
        count = count + 1;
      }
    }
    show(count);
37. 37.🔁 What number does this code show?
    let marks = [5, 13, 10, 16];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
38. 38.🔁 What number does this code show?
    let marks = [2, 9, 5];
    let total = 0;
    for (let i = 0; i < marks.length; i++) {
      total = total + marks[i];
    }
    show(total);
39. 39.🔁 What is the LAST line this code shows?
    let names = ["Aman", "Zoya", "Riya"];
    for (let i = 0; i < names.length; i++) {
      show("Hi, " + names[i]);
    } (a) Hi, Zoya (b) Hi, Riya (c) Hi, Aman
40. 40.🔁 What number does this code show?
    let steps = [95, 72, 42, 13, 94];
    let count = 0;
    for (let i = 0; i < steps.length; i++) {
      if (steps[i] >= 40) {
        count = count + 1;
      }
    }
    show(count);

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