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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 589 · 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.🧰 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(11));
  2. 2.🧰 How do you run (call) a function called greet? (a) greet() (b) run greet (c) #greet (d) greet[]
  3. 3.🧰 Why write a function? (a) to hide errors (b) to reuse code (c) to make code longer (d) to slow the app
  4. 4.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(0));
  5. 5.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(11));
  6. 6.🧰 What does return do in a function? (a) deletes the app (b) repeats the code (c) closes the screen (d) sends back a value
  7. 7.🧰 What is a function? (a) a screen size (b) a list of colours (c) a type of phone (d) a named block of code
  8. 8.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(60, 4));
  9. 9.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Aman"));     (a) Aman (b) Hello, Aman! (c) greet (d) Hello, name!
  10. 10.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(1));
  11. 11.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(4));
  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 20;
    }
    show(fee(6) + fee(1));
  13. 13.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(25, 3));
  14. 14.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(95, 6));
  15. 15.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Zoya"));     (a) Welcome, Zoya! (b) Welcome, name! (c) greet (d) Zoya
  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 30;
    }
    show(fee(3) + fee(9));
  17. 17.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(45, 2));
  18. 18.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya"));     (a) Zoya (b) Hi, Zoya! (c) greet (d) Hi, name!
  19. 19.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(3));
  20. 20.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(35));
  21. 21.🧰 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(1) + fee(1));
  22. 22.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(20, 2));
  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 50;
    }
    show(fee(3) + fee(11));
  24. 24.🧰 In function tip(bill), what is bill? (a) a screen (b) a loop (c) an event (d) a parameter
  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(11) + fee(5));
  26. 26.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Riya"));     (a) greet (b) Welcome, Riya! (c) Welcome, name! (d) Riya
  27. 27.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(36));
  28. 28.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(1));
  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 20;
    }
    show(fee(3) + fee(1));
  30. 30.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Aman"));     (a) Aman (b) Well done, name! (c) Well done, Aman! (d) greet
  31. 31.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(28));
  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 20;
    }
    show(fee(2) + fee(12));
  33. 33.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(1));
  34. 34.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(90, 2));
  35. 35.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya"));     (a) greet (b) Hello, name! (c) Riya (d) Hello, Riya!
  36. 36.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(3));
  37. 37.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(6));
  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 20;
    }
    show(fee(4) + fee(12));
  39. 39.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Arjun"));     (a) greet (b) Well done, Arjun! (c) Well done, name! (d) Arjun
  40. 40.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(18));

Answer key

  1. 50
  2. greet()
  3. to reuse code
  4. 40
  5. 22
  6. sends back a value
  7. a named block of code
  8. 240
  9. Hello, Aman!
  10. 70
  11. 70
  12. 20
  13. 75
  14. 570
  15. Welcome, Zoya!
  16. 30
  17. 90
  18. Hi, Zoya!
  19. 9
  20. 70
  21. 0
  22. 40
  23. 50
  24. a parameter
  25. 120
  26. Welcome, Riya!
  27. 108
  28. 40
  29. 0
  30. Well done, Aman!
  31. 84
  32. 20
  33. 50
  34. 180
  35. Hello, Riya!
  36. 60
  37. 18
  38. 20
  39. Well done, Arjun!
  40. 36

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