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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 640 · 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 type of phone (b) a screen size (c) a named block of code (d) a list of colours
  2. 2.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(29));
  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(8) + fee(4));
  4. 4.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Arjun"));     (a) Arjun (b) greet (c) Welcome, name! (d) Welcome, Arjun!
  5. 5.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(2));
  6. 6.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(100, 6));
  7. 7.🧰 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(9));
  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(9) + fee(8));
  9. 9.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(65, 6));
  10. 10.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 2));
  11. 11.🧰 In function tip(bill), what is bill? (a) a parameter (b) an event (c) a loop (d) a screen
  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 40;
    }
    show(fee(10) + 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(5) + fee(3));
  14. 14.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Meera"));     (a) Well done, Meera! (b) Meera (c) greet (d) Well done, name!
  15. 15.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(95, 6));
  16. 16.🧰 What does return do in a function? (a) deletes the app (b) closes the screen (c) repeats the code (d) sends back a value
  17. 17.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Arjun"));     (a) Arjun (b) Hello, Arjun! (c) Hello, name! (d) greet
  18. 18.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(45, 2));
  19. 19.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(1));
  20. 20.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Kabir"));     (a) Hi, Kabir! (b) Hi, name! (c) Kabir (d) greet
  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 30;
    }
    show(fee(3) + fee(11));
  22. 22.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Zoya"));     (a) Welcome, Zoya! (b) greet (c) Welcome, name! (d) Zoya
  23. 23.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(3));
  24. 24.🧰 How do you run (call) a function called greet? (a) greet() (b) #greet (c) run greet (d) greet[]
  25. 25.🧰 Why write a function? (a) to hide errors (b) to slow the app (c) to reuse code (d) to make code longer
  26. 26.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(6));
  27. 27.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(4));
  28. 28.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(14));
  29. 29.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Zoya"));     (a) greet (b) Hello, Zoya! (c) Hello, name! (d) Zoya
  30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 2));
  31. 31.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya"));     (a) Hi, Zoya! (b) Zoya (c) Hi, name! (d) greet
  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(7) + fee(10));
  33. 33.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(40, 6));
  34. 34.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(75, 5));
  35. 35.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(21));
  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(12) + fee(11));
  37. 37.🧰 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(2));
  38. 38.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(95, 5));
  39. 39.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(15, 2));
  40. 40.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(4));

Answer key

  1. a named block of code
  2. 87
  3. 60
  4. Welcome, Arjun!
  5. 80
  6. 600
  7. 80
  8. 60
  9. 390
  10. 140
  11. a parameter
  12. 80
  13. 60
  14. Well done, Meera!
  15. 570
  16. sends back a value
  17. Hello, Arjun!
  18. 90
  19. 70
  20. Hi, Kabir!
  21. 30
  22. Welcome, Zoya!
  23. 70
  24. greet()
  25. to reuse code
  26. 12
  27. 60
  28. 28
  29. Hello, Zoya!
  30. 20
  31. Hi, Zoya!
  32. 60
  33. 240
  34. 375
  35. 63
  36. 40
  37. 60
  38. 475
  39. 30
  40. 90

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