App Dev Worksheet: Functions

App development lesson 20: Functions · Set 752 · 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 does return do in a function? (a) sends back a value (b) repeats the code (c) closes the screen (d) deletes the app
2. 2.🧰 What is a function? (a) a type of phone (b) a screen size (c) a list of colours (d) a named block of code
3. 3.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(50, 3));
4. 4.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(16));
5. 5.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(6));
6. 6.🧰 What does this code show?
   function greet(name) {
     return "Welcome, " + name + "!";
   }
   show(greet("Zoya")); (a) greet (b) Welcome, name! (c) Welcome, Zoya! (d) Zoya
7. 7.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(23));
8. 8.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(40));
9. 9.🧰 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(9) + fee(4));
10. 10.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Zoya")); (a) Hello, name! (b) greet (c) Zoya (d) Hello, Zoya!
11. 11.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(12));
12. 12.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(31));
13. 13.🧰 In function tip(bill), what is bill? (a) a parameter (b) a loop (c) a screen (d) an event
14. 14.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(19));
15. 15.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(0));
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 20;
    }
    show(fee(8) + fee(3));
17. 17.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Zoya")); (a) Well done, name! (b) Well done, Zoya! (c) Zoya (d) greet
18. 18.🧰 Why write a function? (a) to make code longer (b) to slow the app (c) to hide errors (d) to reuse code
19. 19.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(15));
20. 20.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(45, 6));
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 40;
    }
    show(fee(7) + fee(11));
22. 22.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(29));
23. 23.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(1));
24. 24.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(50, 4));
25. 25.🧰 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(10));
26. 26.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(2));
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 20;
    }
    show(fee(1) + fee(10));
28. 28.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Riya")); (a) greet (b) Hi, Riya! (c) Riya (d) Hi, name!
29. 29.🧰 How do you run (call) a function called greet? (a) run greet (b) greet() (c) greet[] (d) #greet
30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 6));
31. 31.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(30));
32. 32.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(1));
33. 33.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 4));
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 50;
    }
    show(fee(8) + fee(2));
35. 35.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(3));
36. 36.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(18));
37. 37.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 5));
38. 38.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(9));
39. 39.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 3));
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 60;
    }
    show(fee(2) + fee(12));

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