App Dev Worksheet: Functions

App development lesson 20: Functions · Set 827 · 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.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(15));
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 60;
   }
   show(fee(5) + fee(8));
3. 3.🧰 Why write a function? (a) to hide errors (b) to slow the app (c) to make code longer (d) to reuse code
4. 4.🧰 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(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 20;
   }
   show(fee(2) + fee(5));
6. 6.🧰 What is a function? (a) a named block of code (b) a type of phone (c) a screen size (d) a list of colours
7. 7.🧰 What does this code show?
   function greet(name) {
     return "Hi, " + name + "!";
   }
   show(greet("Kabir")); (a) Hi, name! (b) greet (c) Hi, Kabir! (d) Kabir
8. 8.🧰 In function tip(bill), what is bill? (a) an event (b) a parameter (c) a screen (d) a loop
9. 9.🧰 How do you run (call) a function called greet? (a) run greet (b) #greet (c) greet() (d) greet[]
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 20;
    }
    show(fee(3) + fee(6));
11. 11.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(39));
12. 12.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(2));
13. 13.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(2));
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(2) + fee(11));
15. 15.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(33));
16. 16.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(24));
17. 17.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(5));
18. 18.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(12));
19. 19.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(2));
20. 20.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(35, 2));
21. 21.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(26));
22. 22.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(95, 5));
23. 23.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(20, 3));
24. 24.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(4));
25. 25.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(45, 5));
26. 26.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(22));
27. 27.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(4));
28. 28.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(85, 4));
29. 29.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(40, 5));
30. 30.🧰 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(6));
31. 31.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(22));
32. 32.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(10));
33. 33.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(3));
34. 34.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 2));
35. 35.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Meera")); (a) Well done, Meera! (b) greet (c) Well done, name! (d) Meera
36. 36.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Arjun")); (a) greet (b) Arjun (c) Hi, Arjun! (d) Hi, name!
37. 37.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(1));
38. 38.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(1));
39. 39.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(14));
40. 40.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(19));

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