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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 587 · 40 questions
TalentJR

Developer's tip (Write once, use often): function name(parameter) { …; return result; } — call it with name(value). Work out each call separately, then finish the line. Inside a function, if / return can give different results for different inputs.

NameDateTime takenScore ___ / 40
  1. 1.🧰 What does return do in a function? (a) closes the screen (b) deletes the app (c) sends back a value (d) repeats the code
  2. 2.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(0));
  3. 3.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Arjun"));     (a) Hi, Arjun! (b) Arjun (c) Hi, name! (d) greet
  4. 4.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(5));
  5. 5.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(40));
  6. 6.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(1));
  7. 7.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(2));
  8. 8.🧰 Why write a function? (a) to make code longer (b) to hide errors (c) to reuse code (d) to slow the app
  9. 9.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(0));
  10. 10.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 4));
  11. 11.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 6));
  12. 12.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya"));     (a) Hi, name! (b) Zoya (c) greet (d) Hi, Zoya!
  13. 13.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(17));
  14. 14.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(5));
  15. 15.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(4));
  16. 16.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 50;
    }
    show(fee(10) + fee(4));
  17. 17.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(6));
  18. 18.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(12));
  19. 19.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(14));
  20. 20.🧰 How do you run (call) a function called greet? (a) greet[] (b) #greet (c) greet() (d) run greet
  21. 21.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(3));
  22. 22.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya"));     (a) Riya (b) Hello, Riya! (c) Hello, name! (d) greet
  23. 23.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(39));
  24. 24.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Zoya"));     (a) Zoya (b) greet (c) Welcome, Zoya! (d) Welcome, name!
  25. 25.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Riya"));     (a) Hi, name! (b) Riya (c) greet (d) Hi, Riya!
  26. 26.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 30;
    }
    show(fee(10) + fee(1));
  27. 27.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(3));
  28. 28.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(30));
  29. 29.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 60;
    }
    show(fee(3) + fee(11));
  30. 30.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(4));
  31. 31.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Riya"));     (a) Riya (b) greet (c) Well done, Riya! (d) Well done, name!
  32. 32.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(95, 6));
  33. 33.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Meera"));     (a) Hello, Meera! (b) Meera (c) Hello, name! (d) greet
  34. 34.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(4));
  35. 35.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 50;
    }
    show(fee(6) + fee(11));
  36. 36.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(13));
  37. 37.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Meera"));     (a) Meera (b) Well done, Meera! (c) Well done, name! (d) greet
  38. 38.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 50;
    }
    show(fee(11) + fee(7));
  39. 39.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 30;
    }
    show(fee(10) + fee(4));
  40. 40.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(32));

Answer key

  1. sends back a value
  2. 30
  3. Hi, Arjun!
  4. 80
  5. 120
  6. 30
  7. 50
  8. to reuse code
  9. 20
  10. 120
  11. 420
  12. Hi, Zoya!
  13. 34
  14. 100
  15. 90
  16. 50
  17. 12
  18. 36
  19. 28
  20. greet()
  21. 50
  22. Hello, Riya!
  23. 117
  24. Welcome, Zoya!
  25. Hi, Riya!
  26. 30
  27. 90
  28. 90
  29. 60
  30. 8
  31. Well done, Riya!
  32. 570
  33. Hello, Meera!
  34. 80
  35. 100
  36. 26
  37. Well done, Meera!
  38. 100
  39. 30
  40. 96

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