App Dev Worksheet: Functions

App development lesson 20: Functions · Set 441 · 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 double(n) {
     return n * 2;
   }
   show(double(8));
2. 2.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(35, 5));
3. 3.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(2) + points(3));
4. 4.🧰 What is a function? (a) a screen size (b) a named block of code (c) a type of phone (d) a list of colours
5. 5.🧰 Why write a function? (a) to slow the app (b) to reuse code (c) to hide errors (d) to make code longer
6. 6.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(50, 4));
7. 7.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(36));
8. 8.🧰 What does this code show?
   function greet(name) {
     return "Welcome, " + name + "!";
   }
   show(greet("Arjun")); (a) Welcome, Arjun! (b) Arjun (c) Welcome, name! (d) greet
9. 9.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(5) + points(0));
10. 10.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(5));
11. 11.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(25, 2));
12. 12.🧰 In function tip(bill), what is bill? (a) a parameter (b) a screen (c) an event (d) a loop
13. 13.🧰 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(5) + fee(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(3) + fee(6));
15. 15.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(100, 5));
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 total(price, qty) {
      return price * qty;
    }
    show(total(70, 3));
18. 18.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(15));
19. 19.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(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(6) + fee(5));
21. 21.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(75, 2));
22. 22.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Arjun")); (a) Hi, name! (b) Arjun (c) greet (d) Hi, Arjun!
23. 23.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(4));
24. 24.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(4));
25. 25.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(2));
26. 26.🧰 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
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(1) + fee(3));
28. 28.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Aman")); (a) Hello, name! (b) greet (c) Hello, Aman! (d) Aman
29. 29.🧰 What does return do in a function? (a) closes the screen (b) repeats the code (c) sends back a value (d) deletes the app
30. 30.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(32));
31. 31.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya")); (a) greet (b) Hello, name! (c) Riya (d) Hello, Riya!
32. 32.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Riya")); (a) greet (b) Well done, name! (c) Riya (d) Well done, Riya!
33. 33.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(50, 5));
34. 34.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(20, 5));
35. 35.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(0));
36. 36.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(13));
37. 37.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(1));
38. 38.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(20));
39. 39.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(15));
40. 40.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(95, 6));

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