App Dev Worksheet: Functions

App development lesson 20: Functions · Set 153 · 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) repeats the code (b) sends back a value (c) deletes the app (d) closes the screen
2. 2.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(60, 6));
3. 3.🧰 What does this code show?
   function greet(name) {
     return "Welcome, " + name + "!";
   }
   show(greet("Zoya")); (a) Welcome, Zoya! (b) Welcome, name! (c) Zoya (d) greet
4. 4.🧰 How do you run (call) a function called greet? (a) #greet (b) greet[] (c) greet() (d) run greet
5. 5.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(10));
6. 6.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(2) + points(5));
7. 7.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(20, 2));
8. 8.🧰 What is a function? (a) a type of phone (b) a named block of code (c) a screen size (d) a list of colours
9. 9.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(38));
10. 10.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(13));
11. 11.🧰 Why write a function? (a) to make code longer (b) to hide errors (c) to slow the app (d) to reuse code
12. 12.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(28));
13. 13.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(2));
14. 14.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(20, 4));
15. 15.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Aman")); (a) Aman (b) greet (c) Hi, Aman! (d) Hi, name!
16. 16.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(25, 4));
17. 17.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 2));
18. 18.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(45, 2));
19. 19.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(40));
20. 20.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(100, 3));
21. 21.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(35, 3));
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 20;
    }
    show(fee(4) + fee(6));
23. 23.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(6));
24. 24.🧰 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(8) + fee(8));
25. 25.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya")); (a) Hello, name! (b) Riya (c) greet (d) Hello, Riya!
26. 26.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(95, 4));
27. 27.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Riya")); (a) Riya (b) Hi, name! (c) Hi, Riya! (d) greet
28. 28.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Kabir")); (a) Hello, name! (b) Kabir (c) Hello, Kabir! (d) greet
29. 29.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(1));
30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 6));
31. 31.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(14));
32. 32.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(4));
33. 33.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Meera")); (a) greet (b) Hi, name! (c) Meera (d) Hi, Meera!
34. 34.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(0));
35. 35.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(35, 6));
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(3) + fee(12));
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 30;
    }
    show(fee(1) + fee(8));
38. 38.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(30));
39. 39.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Kabir")); (a) greet (b) Kabir (c) Hi, name! (d) Hi, Kabir!
40. 40.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(11));

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