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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 671 · 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(10, 3));
  2. 2.🧰 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(4));
  3. 3.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(30));
  4. 4.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Kabir"));     (a) greet (b) Welcome, Kabir! (c) Kabir (d) Welcome, name!
  5. 5.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(5));
  6. 6.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Meera"));     (a) greet (b) Well done, Meera! (c) Well done, name! (d) Meera
  7. 7.🧰 What is a function? (a) a named block of code (b) a screen size (c) a type of phone (d) a list of colours
  8. 8.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(22));
  9. 9.🧰 How do you run (call) a function called greet? (a) greet() (b) greet[] (c) run greet (d) #greet
  10. 10.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(1));
  11. 11.🧰 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(3));
  12. 12.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Aman"));     (a) greet (b) Aman (c) Hello, Aman! (d) Hello, name!
  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 20;
    }
    show(fee(8) + fee(8));
  14. 14.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(24));
  15. 15.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Arjun"));     (a) Well done, name! (b) Arjun (c) Well done, Arjun! (d) greet
  16. 16.🧰 In function tip(bill), what is bill? (a) a parameter (b) a screen (c) an event (d) a loop
  17. 17.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(30));
  18. 18.🧰 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));
  19. 19.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 3));
  20. 20.🧰 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(7) + fee(10));
  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 20;
    }
    show(fee(8) + fee(7));
  22. 22.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Zoya"));     (a) Zoya (b) Welcome, Zoya! (c) greet (d) Welcome, name!
  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 40;
    }
    show(fee(5) + fee(8));
  24. 24.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(35));
  25. 25.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya"));     (a) greet (b) Hi, Zoya! (c) Hi, name! (d) Zoya
  26. 26.🧰 Why write a function? (a) to slow the app (b) to reuse code (c) to make code longer (d) to hide errors
  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 30;
    }
    show(fee(7) + fee(11));
  28. 28.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(0));
  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(7));
  30. 30.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(34));
  31. 31.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(4));
  32. 32.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Aman"));     (a) greet (b) Aman (c) Well done, Aman! (d) Well done, name!
  33. 33.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Kabir"));     (a) Well done, Kabir! (b) Well done, name! (c) greet (d) Kabir
  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(12) + fee(1));
  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 30;
    }
    show(fee(3) + fee(10));
  36. 36.🧰 What does return do in a function? (a) sends back a value (b) closes the screen (c) deletes the app (d) repeats the code
  37. 37.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(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(5) + fee(12));
  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 20;
    }
    show(fee(3) + fee(2));
  40. 40.🧰 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(5));

Answer key

  1. 30
  2. 0
  3. 60
  4. Welcome, Kabir!
  5. 110
  6. Well done, Meera!
  7. a named block of code
  8. 44
  9. greet()
  10. 40
  11. 60
  12. Hello, Aman!
  13. 40
  14. 72
  15. Well done, Arjun!
  16. a parameter
  17. 90
  18. 40
  19. 240
  20. 100
  21. 40
  22. Welcome, Zoya!
  23. 80
  24. 70
  25. Hi, Zoya!
  26. to reuse code
  27. 60
  28. 30
  29. 20
  30. 68
  31. 8
  32. Well done, Aman!
  33. Well done, Kabir!
  34. 40
  35. 30
  36. sends back a value
  37. 60
  38. 100
  39. 0
  40. 100

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