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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 514 · 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 total(price, qty) {
      return price * qty;
    }
    show(total(100, 2));
  2. 2.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(0));
  3. 3.🧰 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(11) + fee(7));
  4. 4.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(4));
  5. 5.🧰 Why write a function? (a) to hide errors (b) to make code longer (c) to slow the app (d) to reuse code
  6. 6.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Zoya"));     (a) greet (b) Zoya (c) Well done, Zoya! (d) Well done, name!
  7. 7.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Zoya"));     (a) Welcome, Zoya! (b) greet (c) Zoya (d) Welcome, name!
  8. 8.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(36));
  9. 9.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(2));
  10. 10.🧰 What does return do in a function? (a) repeats the code (b) closes the screen (c) sends back a value (d) deletes the app
  11. 11.🧰 How do you run (call) a function called greet? (a) greet[] (b) run greet (c) #greet (d) greet()
  12. 12.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Meera"));     (a) Well done, name! (b) Meera (c) Well done, Meera! (d) greet
  13. 13.🧰 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(2) + fee(1));
  14. 14.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Zoya"));     (a) Hello, name! (b) Hello, Zoya! (c) Zoya (d) greet
  15. 15.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(85, 2));
  16. 16.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(1));
  17. 17.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(50, 4));
  18. 18.🧰 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(9) + fee(1));
  19. 19.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(3));
  20. 20.🧰 What is a function? (a) a named block of code (b) a type of phone (c) a list of colours (d) a screen size
  21. 21.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(29));
  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 60;
    }
    show(fee(7) + fee(8));
  23. 23.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya"));     (a) Riya (b) greet (c) Hello, name! (d) Hello, Riya!
  24. 24.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(60, 5));
  25. 25.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Aman"));     (a) Aman (b) greet (c) Well done, name! (d) Well done, Aman!
  26. 26.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(20, 3));
  27. 27.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Meera"));     (a) Hi, name! (b) greet (c) Hi, Meera! (d) Meera
  28. 28.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(38));
  29. 29.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(50, 2));
  30. 30.🧰 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(6) + fee(3));
  31. 31.🧰 In function tip(bill), what is bill? (a) a parameter (b) a screen (c) a loop (d) an event
  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 40;
    }
    show(fee(3) + fee(2));
  33. 33.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(12));
  34. 34.🧰 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(10));
  35. 35.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(5));
  36. 36.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Riya"));     (a) greet (b) Hi, Riya! (c) Hi, name! (d) Riya
  37. 37.🧰 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(5) + fee(11));
  38. 38.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Arjun"));     (a) greet (b) Hello, name! (c) Hello, Arjun! (d) Arjun
  39. 39.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(45, 4));
  40. 40.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 2));

Answer key

  1. 200
  2. 60
  3. 120
  4. 90
  5. to reuse code
  6. Well done, Zoya!
  7. Welcome, Zoya!
  8. 72
  9. 50
  10. sends back a value
  11. greet()
  12. Well done, Meera!
  13. 0
  14. Hello, Zoya!
  15. 170
  16. 40
  17. 200
  18. 30
  19. 90
  20. a named block of code
  21. 58
  22. 120
  23. Hello, Riya!
  24. 300
  25. Well done, Aman!
  26. 60
  27. Hi, Meera!
  28. 76
  29. 100
  30. 60
  31. a parameter
  32. 0
  33. 24
  34. 100
  35. 80
  36. Hi, Riya!
  37. 40
  38. Hello, Arjun!
  39. 180
  40. 60

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