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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 123 · 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(95, 2));
  2. 2.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Meera"));     (a) Hello, name! (b) Hello, Meera! (c) Meera (d) greet
  3. 3.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(18));
  4. 4.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(0));
  5. 5.🧰 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(7));
  6. 6.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(5));
  7. 7.🧰 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(8) + fee(7));
  8. 8.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 6));
  9. 9.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(4));
  10. 10.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(5));
  11. 11.🧰 Why write a function? (a) to make code longer (b) to slow the app (c) to reuse code (d) to hide errors
  12. 12.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(36));
  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 40;
    }
    show(fee(5) + fee(9));
  14. 14.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(40, 6));
  15. 15.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(60, 2));
  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 60;
    }
    show(fee(12) + fee(12));
  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 20;
    }
    show(fee(3) + fee(4));
  18. 18.🧰 What is a function? (a) a list of colours (b) a type of phone (c) a screen size (d) a named block of code
  19. 19.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(8));
  20. 20.🧰 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(5));
  21. 21.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(2));
  22. 22.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(26));
  23. 23.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(4));
  24. 24.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Kabir"));     (a) Kabir (b) greet (c) Well done, Kabir! (d) Well done, name!
  25. 25.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Aman"));     (a) greet (b) Welcome, Aman! (c) Aman (d) Welcome, name!
  26. 26.🧰 In function tip(bill), what is bill? (a) a loop (b) an event (c) a parameter (d) a screen
  27. 27.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya"));     (a) greet (b) Riya (c) Hello, name! (d) Hello, Riya!
  28. 28.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Aman"));     (a) greet (b) Aman (c) Hello, name! (d) Hello, Aman!
  29. 29.🧰 What does return do in a function? (a) deletes the app (b) closes the screen (c) sends back a value (d) repeats the code
  30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 6));
  31. 31.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Riya"));     (a) Hi, name! (b) greet (c) Hi, Riya! (d) Riya
  32. 32.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Meera"));     (a) greet (b) Meera (c) Well done, Meera! (d) Well done, name!
  33. 33.🧰 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(3) + fee(5));
  34. 34.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(4));
  35. 35.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(9));
  36. 36.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(3));
  37. 37.🧰 How do you run (call) a function called greet? (a) greet() (b) run greet (c) greet[] (d) #greet
  38. 38.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(95, 6));
  39. 39.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(3));
  40. 40.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 6));

Answer key

  1. 190
  2. Hello, Meera!
  3. 54
  4. 50
  5. 30
  6. 70
  7. 120
  8. 180
  9. 100
  10. 90
  11. to reuse code
  12. 108
  13. 80
  14. 240
  15. 120
  16. 120
  17. 0
  18. a named block of code
  19. 24
  20. 40
  21. 40
  22. 78
  23. 60
  24. Well done, Kabir!
  25. Welcome, Aman!
  26. a parameter
  27. Hello, Riya!
  28. Hello, Aman!
  29. sends back a value
  30. 330
  31. Hi, Riya!
  32. Well done, Meera!
  33. 20
  34. 70
  35. 18
  36. 50
  37. greet()
  38. 570
  39. 9
  40. 480

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