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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 727 · 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 does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Arjun"));     (a) Arjun (b) Hello, name! (c) greet (d) Hello, Arjun!
  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(2) + fee(12));
  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 60;
    }
    show(fee(5) + 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 60;
    }
    show(fee(12) + fee(12));
  5. 5.🧰 How do you run (call) a function called greet? (a) #greet (b) run greet (c) greet() (d) greet[]
  6. 6.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Aman"));     (a) Hi, Aman! (b) greet (c) Aman (d) Hi, name!
  7. 7.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Kabir"));     (a) Welcome, name! (b) greet (c) Welcome, Kabir! (d) Kabir
  8. 8.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Arjun"));     (a) Welcome, Arjun! (b) Arjun (c) Welcome, name! (d) greet
  9. 9.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Kabir"));     (a) greet (b) Hello, name! (c) Hello, Kabir! (d) Kabir
  10. 10.🧰 What does return do in a function? (a) repeats the code (b) deletes the app (c) sends back a value (d) closes the screen
  11. 11.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(5));
  12. 12.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(20));
  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 50;
    }
    show(fee(8) + fee(9));
  14. 14.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(22));
  15. 15.🧰 Why write a function? (a) to hide errors (b) to slow the app (c) to make code longer (d) to reuse code
  16. 16.🧰 What is a function? (a) a list of colours (b) a named block of code (c) a type of phone (d) a screen size
  17. 17.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 3));
  18. 18.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(39));
  19. 19.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Zoya"));     (a) Welcome, name! (b) greet (c) Welcome, Zoya! (d) Zoya
  20. 20.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Zoya"));     (a) Zoya (b) greet (c) Hello, name! (d) Hello, Zoya!
  21. 21.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(20, 5));
  22. 22.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya"));     (a) Hi, name! (b) Zoya (c) greet (d) Hi, Zoya!
  23. 23.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(65, 5));
  24. 24.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Meera"));     (a) Hello, name! (b) greet (c) Hello, Meera! (d) Meera
  25. 25.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 4));
  26. 26.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(9));
  27. 27.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(2));
  28. 28.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Riya"));     (a) greet (b) Well done, Riya! (c) Riya (d) Well done, name!
  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 30;
    }
    show(fee(12) + fee(9));
  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 20;
    }
    show(fee(5) + fee(1));
  31. 31.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(15));
  32. 32.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(20, 3));
  33. 33.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(90, 5));
  34. 34.🧰 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(6) + fee(4));
  35. 35.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 3));
  36. 36.🧰 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(10));
  37. 37.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 5));
  38. 38.🧰 In function tip(bill), what is bill? (a) a parameter (b) a loop (c) an event (d) a screen
  39. 39.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(2));
  40. 40.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(3));

Answer key

  1. Hello, Arjun!
  2. 30
  3. 120
  4. 120
  5. greet()
  6. Hi, Aman!
  7. Welcome, Kabir!
  8. Welcome, Arjun!
  9. Hello, Kabir!
  10. sends back a value
  11. 80
  12. 40
  13. 100
  14. 44
  15. to reuse code
  16. a named block of code
  17. 240
  18. 78
  19. Welcome, Zoya!
  20. Hello, Zoya!
  21. 100
  22. Hi, Zoya!
  23. 325
  24. Hello, Meera!
  25. 280
  26. 18
  27. 70
  28. Well done, Riya!
  29. 60
  30. 20
  31. 45
  32. 60
  33. 450
  34. 40
  35. 90
  36. 20
  37. 400
  38. a parameter
  39. 50
  40. 80

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