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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 361 · 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(20, 4));
  2. 2.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(15, 2));
  3. 3.🧰 What does return do in a function? (a) deletes the app (b) sends back a value (c) closes the screen (d) repeats the code
  4. 4.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(4));
  5. 5.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(0));
  6. 6.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 5));
  7. 7.🧰 In function tip(bill), what is bill? (a) a screen (b) an event (c) a parameter (d) a loop
  8. 8.🧰 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(7));
  9. 9.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(2));
  10. 10.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(3));
  11. 11.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Arjun"));     (a) Welcome, name! (b) greet (c) Welcome, Arjun! (d) Arjun
  12. 12.🧰 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(2) + fee(8));
  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 60;
    }
    show(fee(9) + fee(12));
  14. 14.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(40, 3));
  15. 15.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(20));
  16. 16.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(85, 5));
  17. 17.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Meera"));     (a) Well done, name! (b) Meera (c) Well done, Meera! (d) greet
  18. 18.🧰 Why write a function? (a) to hide errors (b) to reuse code (c) to slow the app (d) to make code longer
  19. 19.🧰 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(10));
  20. 20.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 5));
  21. 21.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Kabir"));     (a) Kabir (b) Hello, Kabir! (c) Hello, name! (d) greet
  22. 22.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Riya"));     (a) Well done, name! (b) greet (c) Riya (d) Well done, Riya!
  23. 23.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Zoya"));     (a) Welcome, name! (b) greet (c) Welcome, Zoya! (d) Zoya
  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 20;
    }
    show(fee(4) + fee(8));
  25. 25.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(5));
  26. 26.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(27));
  27. 27.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Riya"));     (a) Hi, Riya! (b) greet (c) Hi, name! (d) Riya
  28. 28.🧰 How do you run (call) a function called greet? (a) run greet (b) #greet (c) greet[] (d) greet()
  29. 29.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Aman"));     (a) Aman (b) greet (c) Well done, Aman! (d) Well done, name!
  30. 30.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(36));
  31. 31.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(13));
  32. 32.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 5));
  33. 33.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(1));
  34. 34.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(35, 5));
  35. 35.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Arjun"));     (a) Arjun (b) greet (c) Hi, name! (d) Hi, Arjun!
  36. 36.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Arjun"));     (a) Well done, name! (b) Well done, Arjun! (c) greet (d) Arjun
  37. 37.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(100, 4));
  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(6) + fee(9));
  39. 39.🧰 What is a function? (a) a list of colours (b) a type of phone (c) a named block of code (d) a screen size
  40. 40.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 2));

Answer key

  1. 80
  2. 30
  3. sends back a value
  4. 60
  5. 50
  6. 275
  7. a parameter
  8. 60
  9. 50
  10. 50
  11. Welcome, Arjun!
  12. 60
  13. 120
  14. 120
  15. 40
  16. 425
  17. Well done, Meera!
  18. to reuse code
  19. 40
  20. 150
  21. Hello, Kabir!
  22. Well done, Riya!
  23. Welcome, Zoya!
  24. 20
  25. 80
  26. 81
  27. Hi, Riya!
  28. greet()
  29. Well done, Aman!
  30. 72
  31. 39
  32. 50
  33. 30
  34. 175
  35. Hi, Arjun!
  36. Well done, Arjun!
  37. 400
  38. 100
  39. a named block of code
  40. 110

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