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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 829 · 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 hide errors (b) to reuse code (c) to make code longer (d) to slow the app
  2. 2.🧰 What does return do in a function? (a) deletes the app (b) closes the screen (c) repeats the code (d) sends back a value
  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 30;
    }
    show(fee(12) + fee(12));
  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 30;
    }
    show(fee(11) + fee(12));
  5. 5.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(5));
  6. 6.🧰 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(10) + fee(1));
  7. 7.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(45, 3));
  8. 8.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(33));
  9. 9.🧰 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(1));
  10. 10.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Arjun"));     (a) Welcome, name! (b) greet (c) Arjun (d) Welcome, Arjun!
  11. 11.🧰 What is a function? (a) a type of phone (b) a screen size (c) a list of colours (d) a named block of code
  12. 12.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Aman"));     (a) Hello, Aman! (b) greet (c) Hello, name! (d) Aman
  13. 13.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(1));
  14. 14.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Arjun"));     (a) greet (b) Arjun (c) Well done, Arjun! (d) Well done, name!
  15. 15.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(27));
  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 40;
    }
    show(fee(10) + fee(11));
  17. 17.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Kabir"));     (a) Kabir (b) greet (c) Hello, Kabir! (d) Hello, name!
  18. 18.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(14));
  19. 19.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(4));
  20. 20.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(38));
  21. 21.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(13));
  22. 22.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 6));
  23. 23.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Arjun"));     (a) Hello, name! (b) Arjun (c) greet (d) Hello, Arjun!
  24. 24.🧰 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(7) + fee(3));
  25. 25.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(3));
  26. 26.🧰 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(7));
  27. 27.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Zoya"));     (a) Zoya (b) Hello, name! (c) greet (d) Hello, Zoya!
  28. 28.🧰 How do you run (call) a function called greet? (a) greet[] (b) #greet (c) greet() (d) run greet
  29. 29.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(4));
  30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(95, 2));
  31. 31.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 3));
  32. 32.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(8));
  33. 33.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(1));
  34. 34.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(37));
  35. 35.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(90, 3));
  36. 36.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Meera"));     (a) Well done, name! (b) greet (c) Meera (d) Well done, Meera!
  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 40;
    }
    show(fee(3) + fee(2));
  38. 38.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(1));
  39. 39.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Meera"));     (a) greet (b) Meera (c) Welcome, name! (d) Welcome, Meera!
  40. 40.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 5));

Answer key

  1. to reuse code
  2. sends back a value
  3. 60
  4. 60
  5. 10
  6. 60
  7. 135
  8. 66
  9. 0
  10. Welcome, Arjun!
  11. a named block of code
  12. Hello, Aman!
  13. 50
  14. Well done, Arjun!
  15. 81
  16. 80
  17. Hello, Kabir!
  18. 28
  19. 12
  20. 114
  21. 39
  22. 180
  23. Hello, Arjun!
  24. 50
  25. 60
  26. 60
  27. Hello, Zoya!
  28. greet()
  29. 70
  30. 190
  31. 30
  32. 16
  33. 70
  34. 74
  35. 270
  36. Well done, Meera!
  37. 0
  38. 60
  39. Welcome, Meera!
  40. 400

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