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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 858 · 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(14));
  2. 2.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 2));
  3. 3.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(1));
  4. 4.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(100, 6));
  5. 5.🧰 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(1));
  6. 6.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(1));
  7. 7.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(32));
  8. 8.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(0));
  9. 9.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(6));
  10. 10.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(4));
  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 50;
    }
    show(fee(2) + fee(6));
  12. 12.🧰 How do you run (call) a function called greet? (a) greet[] (b) #greet (c) greet() (d) run greet
  13. 13.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(50, 3));
  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 20;
    }
    show(fee(6) + fee(6));
  15. 15.🧰 In function tip(bill), what is bill? (a) a screen (b) a loop (c) an event (d) a parameter
  16. 16.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(3));
  17. 17.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(21));
  18. 18.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Meera"));     (a) Hi, name! (b) Hi, Meera! (c) greet (d) Meera
  19. 19.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(21));
  20. 20.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Riya"));     (a) greet (b) Riya (c) Welcome, Riya! (d) Welcome, name!
  21. 21.🧰 Why write a function? (a) to hide errors (b) to reuse code (c) to make code longer (d) to slow the app
  22. 22.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Aman"));     (a) Welcome, Aman! (b) Welcome, name! (c) greet (d) Aman
  23. 23.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya"));     (a) Hi, Zoya! (b) greet (c) Zoya (d) Hi, name!
  24. 24.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Zoya"));     (a) greet (b) Well done, Zoya! (c) Zoya (d) Well done, name!
  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 20;
    }
    show(fee(6) + fee(5));
  26. 26.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Kabir"));     (a) Hi, name! (b) greet (c) Kabir (d) Hi, Kabir!
  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(3) + fee(11));
  28. 28.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya"));     (a) Riya (b) Hello, Riya! (c) greet (d) Hello, name!
  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 50;
    }
    show(fee(1) + fee(7));
  30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(40, 3));
  31. 31.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(12));
  32. 32.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Riya"));     (a) Hi, name! (b) greet (c) Riya (d) Hi, Riya!
  33. 33.🧰 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(7));
  34. 34.🧰 What does return do in a function? (a) repeats the code (b) deletes the app (c) sends back a value (d) closes the screen
  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(4));
  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 60;
    }
    show(fee(11) + fee(12));
  37. 37.🧰 What is a function? (a) a named block of code (b) a screen size (c) a list of colours (d) a type of phone
  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 30;
    }
    show(fee(11) + fee(8));
  39. 39.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(75, 2));
  40. 40.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(29));

Answer key

  1. 42
  2. 60
  3. 50
  4. 600
  5. 60
  6. 60
  7. 64
  8. 20
  9. 18
  10. 90
  11. 50
  12. greet()
  13. 150
  14. 40
  15. a parameter
  16. 9
  17. 42
  18. Hi, Meera!
  19. 63
  20. Welcome, Riya!
  21. to reuse code
  22. Welcome, Aman!
  23. Hi, Zoya!
  24. Well done, Zoya!
  25. 40
  26. Hi, Kabir!
  27. 60
  28. Hello, Riya!
  29. 50
  30. 120
  31. 24
  32. Hi, Riya!
  33. 60
  34. sends back a value
  35. 0
  36. 120
  37. a named block of code
  38. 60
  39. 150
  40. 58

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