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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 450 · 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 points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(0));
  2. 2.🧰 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(2));
  3. 3.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Arjun"));     (a) Hello, Arjun! (b) greet (c) Hello, name! (d) Arjun
  4. 4.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(3));
  5. 5.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(1));
  6. 6.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya"));     (a) Hi, name! (b) greet (c) Hi, Zoya! (d) Zoya
  7. 7.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Zoya"));     (a) Zoya (b) greet (c) Hello, name! (d) Hello, Zoya!
  8. 8.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(7));
  9. 9.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(4));
  10. 10.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Aman"));     (a) Hi, name! (b) Aman (c) Hi, Aman! (d) greet
  11. 11.🧰 How do you run (call) a function called greet? (a) greet[] (b) greet() (c) run greet (d) #greet
  12. 12.🧰 Why write a function? (a) to hide errors (b) to slow the app (c) to make code longer (d) to reuse code
  13. 13.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(12));
  14. 14.🧰 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(11) + fee(7));
  15. 15.🧰 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(4) + fee(7));
  16. 16.🧰 What is a function? (a) a screen size (b) a named block of code (c) a list of colours (d) a type of phone
  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 40;
    }
    show(fee(12) + fee(1));
  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(7) + fee(1));
  19. 19.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(0));
  20. 20.🧰 In function tip(bill), what is bill? (a) a screen (b) an event (c) a parameter (d) a loop
  21. 21.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(75, 4));
  22. 22.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Arjun"));     (a) greet (b) Well done, name! (c) Arjun (d) Well done, Arjun!
  23. 23.🧰 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(4));
  24. 24.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(4));
  25. 25.🧰 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(1) + fee(12));
  26. 26.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(26));
  27. 27.🧰 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(7) + fee(10));
  28. 28.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(16));
  29. 29.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(4));
  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(7) + 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 30;
    }
    show(fee(8) + fee(9));
  32. 32.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(40, 5));
  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 60;
    }
    show(fee(11) + fee(9));
  34. 34.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya"));     (a) Riya (b) greet (c) Hello, name! (d) Hello, Riya!
  35. 35.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Arjun"));     (a) greet (b) Hi, name! (c) Arjun (d) Hi, Arjun!
  36. 36.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(2));
  37. 37.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Meera"));     (a) Meera (b) Hi, name! (c) Hi, Meera! (d) greet
  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 50;
    }
    show(fee(5) + fee(7));
  39. 39.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 4));
  40. 40.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(5));

Answer key

  1. 40
  2. 30
  3. Hello, Arjun!
  4. 60
  5. 70
  6. Hi, Zoya!
  7. Hello, Zoya!
  8. 21
  9. 90
  10. Hi, Aman!
  11. greet()
  12. to reuse code
  13. 36
  14. 40
  15. 50
  16. a named block of code
  17. 40
  18. 30
  19. 20
  20. a parameter
  21. 300
  22. Well done, Arjun!
  23. 60
  24. 100
  25. 20
  26. 52
  27. 80
  28. 32
  29. 12
  30. 120
  31. 60
  32. 200
  33. 120
  34. Hello, Riya!
  35. Hi, Arjun!
  36. 60
  37. Hi, Meera!
  38. 100
  39. 220
  40. 70

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