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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 883 · 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 number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(26));
  2. 2.🧰 What does return do in a function? (a) repeats the code (b) deletes the app (c) sends back a value (d) closes the screen
  3. 3.🧰 What is a function? (a) a named block of code (b) a screen size (c) a type of phone (d) a list of colours
  4. 4.🧰 How do you run (call) a function called greet? (a) greet() (b) run greet (c) #greet (d) greet[]
  5. 5.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(4));
  6. 6.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(17));
  7. 7.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Meera"));     (a) Meera (b) Well done, name! (c) greet (d) Well done, Meera!
  8. 8.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 2));
  9. 9.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(0));
  10. 10.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Aman"));     (a) Hi, Aman! (b) Hi, name! (c) Aman (d) greet
  11. 11.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(60, 6));
  12. 12.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Kabir"));     (a) Kabir (b) greet (c) Hello, Kabir! (d) Hello, name!
  13. 13.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 2));
  14. 14.🧰 In function tip(bill), what is bill? (a) a parameter (b) an event (c) a loop (d) a screen
  15. 15.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(0));
  16. 16.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(39));
  17. 17.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 5));
  18. 18.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(0));
  19. 19.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(2));
  20. 20.🧰 Why write a function? (a) to slow the app (b) to make code longer (c) to reuse code (d) to hide errors
  21. 21.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(33));
  22. 22.🧰 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(4) + fee(12));
  23. 23.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 6));
  24. 24.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(16));
  25. 25.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(23));
  26. 26.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(6));
  27. 27.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 20;
    }
    show(fee(10) + fee(11));
  28. 28.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Zoya"));     (a) Hello, Zoya! (b) Zoya (c) Hello, name! (d) greet
  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 40;
    }
    show(fee(3) + fee(11));
  30. 30.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Meera"));     (a) Hi, name! (b) Hi, Meera! (c) greet (d) Meera
  31. 31.🧰 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(12) + fee(6));
  32. 32.🧰 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(11) + fee(12));
  33. 33.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(6));
  34. 34.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Zoya"));     (a) greet (b) Zoya (c) Well done, name! (d) Well done, Zoya!
  35. 35.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Aman"));     (a) greet (b) Welcome, name! (c) Welcome, Aman! (d) Aman
  36. 36.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 20;
    }
    show(fee(4) + fee(7));
  37. 37.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(0));
  38. 38.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Meera"));     (a) Welcome, name! (b) greet (c) Welcome, Meera! (d) Meera
  39. 39.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(1));
  40. 40.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(20, 6));

Answer key

  1. 52
  2. sends back a value
  3. a named block of code
  4. greet()
  5. 8
  6. 34
  7. Well done, Meera!
  8. 60
  9. 50
  10. Hi, Aman!
  11. 360
  12. Hello, Kabir!
  13. 20
  14. a parameter
  15. 20
  16. 117
  17. 400
  18. 40
  19. 80
  20. to reuse code
  21. 99
  22. 30
  23. 480
  24. 32
  25. 69
  26. 12
  27. 40
  28. Hello, Zoya!
  29. 40
  30. Hi, Meera!
  31. 120
  32. 60
  33. 18
  34. Well done, Zoya!
  35. Welcome, Aman!
  36. 20
  37. 30
  38. Welcome, Meera!
  39. 40
  40. 120

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