App Dev Worksheet: Functions

App development lesson 20: Functions · Set 868 · 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(13));
2. 2.🧰 Why write a function? (a) to make code longer (b) to slow the app (c) to reuse code (d) to hide errors
3. 3.🧰 In function tip(bill), what is bill? (a) a screen (b) a parameter (c) a loop (d) an event
4. 4.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(15, 4));
5. 5.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(3) + points(2));
6. 6.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(3) + points(4));
7. 7.🧰 What does this code show?
   function greet(name) {
     return "Hello, " + name + "!";
   }
   show(greet("Arjun")); (a) Arjun (b) Hello, name! (c) Hello, Arjun! (d) greet
8. 8.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(27));
9. 9.🧰 What does this code show?
   function greet(name) {
     return "Welcome, " + name + "!";
   }
   show(greet("Aman")); (a) Welcome, Aman! (b) Aman (c) greet (d) Welcome, name!
10. 10.🧰 What does return do in a function? (a) deletes the app (b) closes the screen (c) repeats the code (d) sends back a value
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 20;
    }
    show(fee(12) + fee(7));
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(9) + fee(2));
13. 13.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Arjun")); (a) Hi, Arjun! (b) Hi, name! (c) greet (d) Arjun
14. 14.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(15));
15. 15.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya")); (a) Hello, Riya! (b) Hello, name! (c) Riya (d) greet
16. 16.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(100, 2));
17. 17.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(2));
18. 18.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Arjun")); (a) greet (b) Welcome, name! (c) Arjun (d) Welcome, Arjun!
19. 19.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(32));
20. 20.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(40, 5));
21. 21.🧰 What is a function? (a) a list of colours (b) a named block of code (c) a screen size (d) a type of phone
22. 22.🧰 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(10));
23. 23.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(30));
24. 24.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(39));
25. 25.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(0));
26. 26.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Riya")); (a) Riya (b) greet (c) Well done, name! (d) Well done, Riya!
27. 27.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(1));
28. 28.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(50, 6));
29. 29.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(28));
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 20;
    }
    show(fee(9) + fee(3));
31. 31.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Aman")); (a) Well done, name! (b) Aman (c) greet (d) Well done, Aman!
32. 32.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya")); (a) Hi, Zoya! (b) Hi, name! (c) greet (d) Zoya
33. 33.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(40));
34. 34.🧰 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(11) + fee(2));
35. 35.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(30));
36. 36.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 6));
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 50;
    }
    show(fee(5) + fee(3));
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 20;
    }
    show(fee(1) + fee(11));
39. 39.🧰 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(8) + fee(9));
40. 40.🧰 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(3));

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