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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 271 · 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.🧰 In function tip(bill), what is bill? (a) a parameter (b) a loop (c) an event (d) a screen
  2. 2.🧰 What is a function? (a) a list of colours (b) a named block of code (c) a type of phone (d) a screen size
  3. 3.🧰 How do you run (call) a function called greet? (a) run greet (b) #greet (c) greet[] (d) greet()
  4. 4.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(1));
  5. 5.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Riya"));     (a) Hi, Riya! (b) Riya (c) greet (d) Hi, name!
  6. 6.🧰 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(11) + fee(7));
  7. 7.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 4));
  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 60;
    }
    show(fee(3) + fee(3));
  9. 9.🧰 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(10) + fee(3));
  10. 10.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(2));
  11. 11.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(2));
  12. 12.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(9));
  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(3) + fee(8));
  14. 14.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Aman"));     (a) Welcome, Aman! (b) Welcome, name! (c) Aman (d) greet
  15. 15.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya"));     (a) Hi, name! (b) Hi, Zoya! (c) Zoya (d) greet
  16. 16.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(60, 4));
  17. 17.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Aman"));     (a) Well done, name! (b) greet (c) Well done, Aman! (d) Aman
  18. 18.🧰 What does return do in a function? (a) repeats the code (b) sends back a value (c) deletes the app (d) closes the screen
  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 20;
    }
    show(fee(4) + fee(12));
  20. 20.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(16));
  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 40;
    }
    show(fee(1) + fee(9));
  22. 22.🧰 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(10) + fee(9));
  23. 23.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya"));     (a) Hello, Riya! (b) Riya (c) Hello, name! (d) greet
  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 60;
    }
    show(fee(11) + fee(2));
  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 30;
    }
    show(fee(5) + fee(2));
  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(28));
  28. 28.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Kabir"));     (a) Kabir (b) Well done, Kabir! (c) greet (d) Well done, name!
  29. 29.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(34));
  30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 5));
  31. 31.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(27));
  32. 32.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(5));
  33. 33.🧰 Why write a function? (a) to make code longer (b) to reuse code (c) to slow the app (d) to hide errors
  34. 34.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(0));
  35. 35.🧰 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(5) + fee(8));
  36. 36.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(20));
  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 40;
    }
    show(fee(11) + fee(7));
  38. 38.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(14));
  39. 39.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 3));
  40. 40.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(7));

Answer key

  1. a parameter
  2. a named block of code
  3. greet()
  4. 50
  5. Hi, Riya!
  6. 100
  7. 220
  8. 0
  9. 60
  10. 40
  11. 60
  12. 18
  13. 50
  14. Welcome, Aman!
  15. Hi, Zoya!
  16. 240
  17. Well done, Aman!
  18. sends back a value
  19. 20
  20. 32
  21. 40
  22. 120
  23. Hello, Riya!
  24. 60
  25. 30
  26. 87
  27. 56
  28. Well done, Kabir!
  29. 102
  30. 275
  31. 54
  32. 90
  33. to reuse code
  34. 20
  35. 80
  36. 60
  37. 80
  38. 28
  39. 240
  40. 21

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