App Dev Worksheet: Functions

App development lesson 20: Functions · Set 579 · 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 reuse code (b) to slow the app (c) to hide errors (d) to make code longer
2. 2.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(12));
3. 3.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(2) + points(2));
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 50;
   }
   show(fee(6) + fee(3));
5. 5.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(11));
6. 6.🧰 What is a function? (a) a type of phone (b) a screen size (c) a named block of code (d) a list of colours
7. 7.🧰 What does return do in a function? (a) closes the screen (b) sends back a value (c) deletes the app (d) repeats the code
8. 8.🧰 What does this code show?
   function greet(name) {
     return "Hi, " + name + "!";
   }
   show(greet("Arjun")); (a) Hi, Arjun! (b) Arjun (c) greet (d) Hi, name!
9. 9.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(18));
10. 10.🧰 How do you run (call) a function called greet? (a) #greet (b) run greet (c) greet[] (d) greet()
11. 11.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya")); (a) Hi, name! (b) Zoya (c) greet (d) Hi, Zoya!
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 60;
    }
    show(fee(5) + fee(2));
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 50;
    }
    show(fee(3) + fee(11));
14. 14.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(40, 5));
15. 15.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Zoya")); (a) Well done, name! (b) Zoya (c) Well done, Zoya! (d) greet
16. 16.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 4));
17. 17.🧰 In function tip(bill), what is bill? (a) a parameter (b) a loop (c) an event (d) a screen
18. 18.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Aman")); (a) Aman (b) Welcome, Aman! (c) greet (d) Welcome, name!
19. 19.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(30));
20. 20.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(19));
21. 21.🧰 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(9) + fee(1));
22. 22.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(20, 2));
23. 23.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(0));
24. 24.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(85, 6));
25. 25.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(15, 6));
26. 26.🧰 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(7) + fee(6));
27. 27.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 2));
28. 28.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(2));
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 60;
    }
    show(fee(10) + fee(1));
30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 2));
31. 31.🧰 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(8));
32. 32.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(20));
33. 33.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Arjun")); (a) greet (b) Hello, Arjun! (c) Arjun (d) Hello, name!
34. 34.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(0));
35. 35.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(2));
36. 36.🧰 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(1));
37. 37.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(17));
38. 38.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(5));
39. 39.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(39));
40. 40.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(2));

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