App Dev Worksheet: Functions

App development lesson 20: Functions · Set 501 · 40 questions

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.

1. 1.🧰 Why write a function? (a) to hide errors (b) to make code longer (c) to reuse code (d) to slow the app
2. 2.🧰 In function tip(bill), what is bill? (a) a loop (b) a parameter (c) an event (d) a screen
3. 3.🧰 What does return do in a function? (a) closes the screen (b) repeats the code (c) sends back a value (d) deletes the app
4. 4.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(8));
5. 5.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(4) + points(1));
6. 6.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(1) + points(2));
7. 7.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(7));
8. 8.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(3));
9. 9.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(20, 3));
10. 10.🧰 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(9) + fee(9));
11. 11.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(2));
12. 12.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(4));
13. 13.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(6));
14. 14.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(13));
15. 15.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(25, 5));
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(5));
17. 17.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(95, 4));
18. 18.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(23));
19. 19.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(8));
20. 20.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Riya")); (a) Riya (b) greet (c) Hi, name! (d) Hi, Riya!
21. 21.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(26));
22. 22.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Kabir")); (a) Kabir (b) greet (c) Hello, Kabir! (d) Hello, name!
23. 23.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(20));
24. 24.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(25));
25. 25.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Kabir")); (a) Kabir (b) Well done, Kabir! (c) Well done, name! (d) greet
26. 26.🧰 How do you run (call) a function called greet? (a) run greet (b) #greet (c) greet() (d) greet[]
27. 27.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Zoya")); (a) greet (b) Welcome, Zoya! (c) Welcome, name! (d) Zoya
28. 28.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Kabir")); (a) Hi, Kabir! (b) Kabir (c) greet (d) Hi, name!
29. 29.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(0));
30. 30.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(17));
31. 31.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Riya")); (a) Welcome, name! (b) Welcome, Riya! (c) Riya (d) greet
32. 32.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(14));
33. 33.🧰 What is a function? (a) a list of colours (b) a type of phone (c) a screen size (d) a named block of code
34. 34.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 2));
35. 35.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 5));
36. 36.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(28));
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 40;
    }
    show(fee(4) + fee(4));
38. 38.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(1));
39. 39.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(2));
40. 40.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(5));

Free app development lessons, practice and worksheets at talentjr.in/app-development-for-students