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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 186 · 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(17));
  2. 2.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(85, 2));
  3. 3.🧰 How do you run (call) a function called greet? (a) greet() (b) run greet (c) #greet (d) greet[]
  4. 4.🧰 Why write a function? (a) to hide errors (b) to slow the app (c) to reuse code (d) to make code longer
  5. 5.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(0));
  6. 6.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(45, 3));
  7. 7.🧰 In function tip(bill), what is bill? (a) a screen (b) a loop (c) an event (d) a parameter
  8. 8.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(21));
  9. 9.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(16));
  10. 10.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(5));
  11. 11.🧰 What is a function? (a) a list of colours (b) a type of phone (c) a named block of code (d) a screen size
  12. 12.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Kabir"));     (a) Hi, name! (b) Kabir (c) greet (d) Hi, Kabir!
  13. 13.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Arjun"));     (a) Hi, Arjun! (b) Arjun (c) Hi, name! (d) greet
  14. 14.🧰 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(6) + fee(9));
  15. 15.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(40, 5));
  16. 16.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(1));
  17. 17.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 4));
  18. 18.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Aman"));     (a) Hi, name! (b) Aman (c) Hi, Aman! (d) greet
  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 30;
    }
    show(fee(11) + fee(10));
  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 30;
    }
    show(fee(3) + fee(4));
  21. 21.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(0));
  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 20;
    }
    show(fee(11) + fee(8));
  23. 23.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 2));
  24. 24.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Meera"));     (a) Welcome, name! (b) Welcome, Meera! (c) Meera (d) greet
  25. 25.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(4));
  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(9) + fee(7));
  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 60;
    }
    show(fee(10) + fee(2));
  28. 28.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(3));
  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 60;
    }
    show(fee(2) + fee(5));
  30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(35, 3));
  31. 31.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(4));
  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(9));
  33. 33.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(24));
  34. 34.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(23));
  35. 35.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(29));
  36. 36.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Meera"));     (a) Well done, name! (b) Well done, Meera! (c) Meera (d) greet
  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(5) + fee(11));
  38. 38.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Meera"));     (a) Hello, Meera! (b) greet (c) Meera (d) Hello, name!
  39. 39.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Zoya"));     (a) greet (b) Hello, Zoya! (c) Zoya (d) Hello, name!
  40. 40.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(28));

Answer key

  1. 51
  2. 170
  3. greet()
  4. to reuse code
  5. 30
  6. 135
  7. a parameter
  8. 42
  9. 32
  10. 110
  11. a named block of code
  12. Hi, Kabir!
  13. Hi, Arjun!
  14. 100
  15. 200
  16. 40
  17. 220
  18. Hi, Aman!
  19. 60
  20. 0
  21. 20
  22. 40
  23. 110
  24. Welcome, Meera!
  25. 60
  26. 120
  27. 60
  28. 50
  29. 60
  30. 105
  31. 100
  32. 20
  33. 72
  34. 46
  35. 58
  36. Well done, Meera!
  37. 120
  38. Hello, Meera!
  39. Hello, Zoya!
  40. 56

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