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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 327 · 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 is a function? (a) a named block of code (b) a type of phone (c) a list of colours (d) a screen size
  2. 2.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(5));
  3. 3.🧰 How do you run (call) a function called greet? (a) greet() (b) #greet (c) greet[] (d) run greet
  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(7) + fee(6));
  5. 5.🧰 What does return do in a function? (a) repeats the code (b) closes the screen (c) sends back a value (d) deletes the app
  6. 6.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(8));
  7. 7.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Arjun"));     (a) Hello, name! (b) Arjun (c) greet (d) Hello, Arjun!
  8. 8.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya"));     (a) Zoya (b) greet (c) Hi, Zoya! (d) Hi, name!
  9. 9.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Meera"));     (a) Hello, Meera! (b) Hello, name! (c) greet (d) Meera
  10. 10.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Aman"));     (a) Aman (b) Welcome, name! (c) Welcome, Aman! (d) greet
  11. 11.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(29));
  12. 12.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Zoya"));     (a) Zoya (b) Well done, Zoya! (c) greet (d) Well done, name!
  13. 13.🧰 Why write a function? (a) to hide errors (b) to reuse code (c) to slow the app (d) to make code longer
  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 40;
    }
    show(fee(2) + fee(12));
  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 20;
    }
    show(fee(1) + fee(3));
  16. 16.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(1));
  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 30;
    }
    show(fee(10) + fee(12));
  18. 18.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(0));
  19. 19.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(0));
  20. 20.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 5));
  21. 21.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 5));
  22. 22.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(36));
  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(9) + fee(6));
  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 30;
    }
    show(fee(6) + fee(1));
  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 60;
    }
    show(fee(3) + fee(1));
  26. 26.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(29));
  27. 27.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(7));
  28. 28.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(30));
  29. 29.🧰 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(11) + fee(8));
  30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 6));
  31. 31.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(1));
  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(11) + fee(6));
  33. 33.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Aman"));     (a) Hello, name! (b) Aman (c) Hello, Aman! (d) greet
  34. 34.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 5));
  35. 35.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Zoya"));     (a) greet (b) Zoya (c) Hello, Zoya! (d) Hello, name!
  36. 36.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(16));
  37. 37.🧰 In function tip(bill), what is bill? (a) a screen (b) an event (c) a loop (d) a parameter
  38. 38.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya"));     (a) Riya (b) Hello, Riya! (c) Hello, name! (d) greet
  39. 39.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(60, 3));
  40. 40.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(22));

Answer key

  1. a named block of code
  2. 70
  3. greet()
  4. 60
  5. sends back a value
  6. 24
  7. Hello, Arjun!
  8. Hi, Zoya!
  9. Hello, Meera!
  10. Welcome, Aman!
  11. 58
  12. Well done, Zoya!
  13. to reuse code
  14. 40
  15. 0
  16. 40
  17. 60
  18. 30
  19. 50
  20. 350
  21. 50
  22. 72
  23. 120
  24. 30
  25. 0
  26. 87
  27. 14
  28. 90
  29. 80
  30. 180
  31. 30
  32. 60
  33. Hello, Aman!
  34. 400
  35. Hello, Zoya!
  36. 32
  37. a parameter
  38. Hello, Riya!
  39. 180
  40. 66

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