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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 440 · 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 triple(n) {
      return n * 3;
    }
    show(triple(6));
  2. 2.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(100, 5));
  3. 3.🧰 What is a function? (a) a named block of code (b) a screen size (c) a list of colours (d) a type of phone
  4. 4.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Kabir"));     (a) Kabir (b) Hi, Kabir! (c) greet (d) Hi, name!
  5. 5.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(3));
  6. 6.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(7));
  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 30;
    }
    show(fee(4) + fee(3));
  8. 8.🧰 In function tip(bill), what is bill? (a) a parameter (b) a loop (c) a screen (d) an event
  9. 9.🧰 What does return do in a function? (a) closes the screen (b) repeats the code (c) sends back a value (d) deletes the app
  10. 10.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(5));
  11. 11.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(24));
  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 30;
    }
    show(fee(6) + fee(8));
  13. 13.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(36));
  14. 14.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(40, 3));
  15. 15.🧰 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(9) + fee(3));
  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 40;
    }
    show(fee(1) + fee(8));
  17. 17.🧰 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(10));
  18. 18.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Arjun"));     (a) greet (b) Hi, Arjun! (c) Arjun (d) Hi, name!
  19. 19.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(28));
  20. 20.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(12));
  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 60;
    }
    show(fee(7) + fee(3));
  22. 22.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(15));
  23. 23.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Riya"));     (a) Riya (b) greet (c) Hi, Riya! (d) Hi, name!
  24. 24.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 2));
  25. 25.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(35, 6));
  26. 26.🧰 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(4) + fee(5));
  27. 27.🧰 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));
  28. 28.🧰 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(2));
  29. 29.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 6));
  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 50;
    }
    show(fee(9) + fee(11));
  31. 31.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Zoya"));     (a) Zoya (b) Welcome, Zoya! (c) greet (d) Welcome, name!
  32. 32.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Meera"));     (a) Well done, name! (b) greet (c) Well done, Meera! (d) Meera
  33. 33.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 3));
  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(4) + fee(8));
  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 20;
    }
    show(fee(3) + fee(5));
  36. 36.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Meera"));     (a) Hi, name! (b) greet (c) Hi, Meera! (d) Meera
  37. 37.🧰 How do you run (call) a function called greet? (a) greet[] (b) run greet (c) #greet (d) greet()
  38. 38.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(90, 5));
  39. 39.🧰 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(3) + fee(1));
  40. 40.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(30));

Answer key

  1. 18
  2. 500
  3. a named block of code
  4. Hi, Kabir!
  5. 50
  6. 21
  7. 0
  8. a parameter
  9. sends back a value
  10. 90
  11. 48
  12. 60
  13. 108
  14. 120
  15. 20
  16. 40
  17. 120
  18. Hi, Arjun!
  19. 56
  20. 24
  21. 60
  22. 45
  23. Hi, Riya!
  24. 110
  25. 210
  26. 60
  27. 50
  28. 0
  29. 60
  30. 100
  31. Welcome, Zoya!
  32. Well done, Meera!
  33. 210
  34. 40
  35. 20
  36. Hi, Meera!
  37. greet()
  38. 450
  39. 0
  40. 90

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