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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 819 · 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(70, 4));
  2. 2.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(18));
  3. 3.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(0));
  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(2) + fee(7));
  5. 5.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Aman"));     (a) Aman (b) Well done, name! (c) greet (d) Well done, Aman!
  6. 6.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Aman"));     (a) greet (b) Hi, Aman! (c) Aman (d) Hi, name!
  7. 7.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(85, 2));
  8. 8.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(5));
  9. 9.🧰 In function tip(bill), what is bill? (a) a loop (b) a screen (c) a parameter (d) an event
  10. 10.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(37));
  11. 11.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Kabir"));     (a) greet (b) Kabir (c) Welcome, Kabir! (d) Welcome, name!
  12. 12.🧰 Why write a function? (a) to reuse code (b) to hide errors (c) to make code longer (d) to slow the app
  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 20;
    }
    show(fee(8) + fee(8));
  14. 14.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 6));
  15. 15.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(5));
  16. 16.🧰 How do you run (call) a function called greet? (a) greet[] (b) #greet (c) greet() (d) run greet
  17. 17.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(50, 4));
  18. 18.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(3));
  19. 19.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(1));
  20. 20.🧰 What is a function? (a) a type of phone (b) a named block of code (c) a screen size (d) a list of colours
  21. 21.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Zoya"));     (a) Hello, name! (b) Zoya (c) greet (d) Hello, Zoya!
  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(9) + fee(10));
  23. 23.🧰 What does return do in a function? (a) repeats the code (b) deletes the app (c) closes the screen (d) sends back a value
  24. 24.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(38));
  25. 25.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(5));
  26. 26.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Kabir"));     (a) Well done, name! (b) greet (c) Kabir (d) Well done, Kabir!
  27. 27.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(60, 2));
  28. 28.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(0));
  29. 29.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(7));
  30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(75, 4));
  31. 31.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(15));
  32. 32.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya"));     (a) Hello, Riya! (b) Hello, name! (c) greet (d) Riya
  33. 33.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Aman"));     (a) Aman (b) Welcome, name! (c) greet (d) Welcome, Aman!
  34. 34.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Aman"));     (a) Aman (b) Hello, Aman! (c) Hello, name! (d) greet
  35. 35.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(2));
  36. 36.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Arjun"));     (a) Hello, name! (b) greet (c) Arjun (d) Hello, Arjun!
  37. 37.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Riya"));     (a) Riya (b) Welcome, name! (c) greet (d) Welcome, Riya!
  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 30;
    }
    show(fee(10) + fee(1));
  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 50;
    }
    show(fee(8) + fee(5));
  40. 40.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(5));

Answer key

  1. 280
  2. 36
  3. 50
  4. 40
  5. Well done, Aman!
  6. Hi, Aman!
  7. 170
  8. 80
  9. a parameter
  10. 111
  11. Welcome, Kabir!
  12. to reuse code
  13. 40
  14. 60
  15. 100
  16. greet()
  17. 200
  18. 60
  19. 30
  20. a named block of code
  21. Hello, Zoya!
  22. 120
  23. sends back a value
  24. 76
  25. 110
  26. Well done, Kabir!
  27. 120
  28. 60
  29. 21
  30. 300
  31. 30
  32. Hello, Riya!
  33. Welcome, Aman!
  34. Hello, Aman!
  35. 40
  36. Hello, Arjun!
  37. Welcome, Riya!
  38. 30
  39. 100
  40. 70

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