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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 833 · 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 does return do in a function? (a) deletes the app (b) repeats the code (c) closes the screen (d) sends back a value
  2. 2.🧰 What is a function? (a) a type of phone (b) a named block of code (c) a list of colours (d) a screen size
  3. 3.🧰 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(12) + fee(9));
  4. 4.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(10));
  5. 5.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 5));
  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 40;
    }
    show(fee(3) + fee(9));
  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 60;
    }
    show(fee(3) + fee(2));
  8. 8.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(34));
  9. 9.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Arjun"));     (a) Hello, name! (b) Arjun (c) Hello, Arjun! (d) greet
  10. 10.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(0));
  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 40;
    }
    show(fee(3) + fee(10));
  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 40;
    }
    show(fee(4) + fee(12));
  13. 13.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Arjun"));     (a) Well done, name! (b) Well done, Arjun! (c) Arjun (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 60;
    }
    show(fee(12) + fee(5));
  15. 15.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Riya"));     (a) Welcome, name! (b) Riya (c) greet (d) Welcome, Riya!
  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 30;
    }
    show(fee(12) + fee(5));
  17. 17.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(25, 5));
  18. 18.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya"));     (a) Zoya (b) greet (c) Hi, Zoya! (d) Hi, name!
  19. 19.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(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 20;
    }
    show(fee(6) + fee(7));
  21. 21.🧰 How do you run (call) a function called greet? (a) greet() (b) run greet (c) #greet (d) greet[]
  22. 22.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(4));
  23. 23.🧰 In function tip(bill), what is bill? (a) a loop (b) a parameter (c) a screen (d) an event
  24. 24.🧰 Why write a function? (a) to slow the app (b) to make code longer (c) to hide errors (d) to reuse code
  25. 25.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(3));
  26. 26.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(5));
  27. 27.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(5));
  28. 28.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Aman"));     (a) Hi, Aman! (b) Hi, name! (c) Aman (d) greet
  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 30;
    }
    show(fee(6) + fee(6));
  30. 30.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Meera"));     (a) greet (b) Welcome, name! (c) Meera (d) Welcome, Meera!
  31. 31.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(100, 5));
  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 60;
    }
    show(fee(8) + fee(4));
  33. 33.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(25, 6));
  34. 34.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(39));
  35. 35.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(20, 2));
  36. 36.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(0));
  37. 37.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Aman"));     (a) Hello, name! (b) greet (c) Hello, Aman! (d) Aman
  38. 38.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Kabir"));     (a) Kabir (b) Welcome, name! (c) greet (d) Welcome, Kabir!
  39. 39.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 3));
  40. 40.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(17));

Answer key

  1. sends back a value
  2. a named block of code
  3. 100
  4. 30
  5. 400
  6. 40
  7. 0
  8. 68
  9. Hello, Arjun!
  10. 50
  11. 40
  12. 40
  13. Well done, Arjun!
  14. 120
  15. Welcome, Riya!
  16. 60
  17. 125
  18. Hi, Zoya!
  19. 9
  20. 40
  21. greet()
  22. 90
  23. a parameter
  24. to reuse code
  25. 50
  26. 110
  27. 70
  28. Hi, Aman!
  29. 60
  30. Welcome, Meera!
  31. 500
  32. 60
  33. 150
  34. 78
  35. 40
  36. 60
  37. Hello, Aman!
  38. Welcome, Kabir!
  39. 210
  40. 34

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