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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 800 · 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.🧰 Why write a function? (a) to make code longer (b) to slow the app (c) to reuse code (d) to hide errors
  2. 2.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Aman"));     (a) Aman (b) Well done, Aman! (c) greet (d) Well done, name!
  3. 3.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(11));
  4. 4.🧰 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(10) + fee(3));
  5. 5.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(23));
  6. 6.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(2));
  7. 7.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(1));
  8. 8.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 4));
  9. 9.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Riya"));     (a) Welcome, Riya! (b) Riya (c) greet (d) Welcome, name!
  10. 10.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(75, 2));
  11. 11.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Zoya"));     (a) Welcome, name! (b) Welcome, Zoya! (c) Zoya (d) greet
  12. 12.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Arjun"));     (a) greet (b) Arjun (c) Well done, name! (d) Well done, Arjun!
  13. 13.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Kabir"));     (a) Kabir (b) greet (c) Hello, Kabir! (d) Hello, name!
  14. 14.🧰 What is a function? (a) a named block of code (b) a type of phone (c) a screen size (d) a list of colours
  15. 15.🧰 In function tip(bill), what is bill? (a) a screen (b) a parameter (c) a loop (d) an event
  16. 16.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 3));
  17. 17.🧰 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(8) + fee(8));
  18. 18.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(2));
  19. 19.🧰 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(6) + fee(8));
  20. 20.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(5));
  21. 21.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(75, 4));
  22. 22.🧰 What does return do in a function? (a) deletes the app (b) sends back a value (c) repeats the code (d) closes the screen
  23. 23.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(34));
  24. 24.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(5));
  25. 25.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(5));
  26. 26.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(45, 6));
  27. 27.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Meera"));     (a) Meera (b) Hi, name! (c) greet (d) Hi, Meera!
  28. 28.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Riya"));     (a) Hi, Riya! (b) Riya (c) Hi, name! (d) greet
  29. 29.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(36));
  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 50;
    }
    show(fee(9) + fee(10));
  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 20;
    }
    show(fee(2) + fee(12));
  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(9) + fee(3));
  33. 33.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(20, 4));
  34. 34.🧰 How do you run (call) a function called greet? (a) greet[] (b) #greet (c) run greet (d) greet()
  35. 35.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(0));
  36. 36.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya"));     (a) Zoya (b) Hi, name! (c) Hi, Zoya! (d) greet
  37. 37.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(50, 3));
  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 40;
    }
    show(fee(9) + fee(9));
  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 40;
    }
    show(fee(3) + fee(8));
  40. 40.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(1));

Answer key

  1. to reuse code
  2. Well done, Aman!
  3. 22
  4. 40
  5. 69
  6. 60
  7. 70
  8. 280
  9. Welcome, Riya!
  10. 150
  11. Welcome, Zoya!
  12. Well done, Arjun!
  13. Hello, Kabir!
  14. a named block of code
  15. a parameter
  16. 30
  17. 100
  18. 50
  19. 40
  20. 110
  21. 300
  22. sends back a value
  23. 102
  24. 80
  25. 10
  26. 270
  27. Hi, Meera!
  28. Hi, Riya!
  29. 72
  30. 100
  31. 20
  32. 30
  33. 80
  34. greet()
  35. 40
  36. Hi, Zoya!
  37. 150
  38. 80
  39. 40
  40. 60

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