App Dev Worksheet: Functions

App development lesson 20: Functions · Set 700 · 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 total(price, qty) {
     return price * qty;
   }
   show(total(25, 3));
2. 2.🧰 Why write a function? (a) to make code longer (b) to hide errors (c) to reuse code (d) to slow the app
3. 3.🧰 What is a function? (a) a named block of code (b) a list of colours (c) a type of phone (d) a screen size
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 30;
   }
   show(fee(2) + fee(10));
5. 5.🧰 What does this code show?
   function greet(name) {
     return "Welcome, " + name + "!";
   }
   show(greet("Kabir")); (a) Welcome, name! (b) greet (c) Welcome, Kabir! (d) Kabir
6. 6.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(3) + points(5));
7. 7.🧰 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(6));
8. 8.🧰 What does this code show?
   function greet(name) {
     return "Hi, " + name + "!";
   }
   show(greet("Zoya")); (a) Hi, Zoya! (b) Zoya (c) Hi, name! (d) greet
9. 9.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(20, 5));
10. 10.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Aman")); (a) Hi, Aman! (b) Hi, name! (c) Aman (d) greet
11. 11.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(39));
12. 12.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Aman")); (a) Hello, name! (b) greet (c) Aman (d) Hello, Aman!
13. 13.🧰 How do you run (call) a function called greet? (a) run greet (b) greet[] (c) #greet (d) greet()
14. 14.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(9));
15. 15.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Kabir")); (a) Kabir (b) Hi, name! (c) greet (d) Hi, Kabir!
16. 16.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Riya")); (a) Well done, Riya! (b) greet (c) Riya (d) Well done, name!
17. 17.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(2));
18. 18.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(25));
19. 19.🧰 In function tip(bill), what is bill? (a) a loop (b) an event (c) a screen (d) a parameter
20. 20.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(4));
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 20;
    }
    show(fee(2) + fee(3));
22. 22.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(1));
23. 23.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Kabir")); (a) Well done, Kabir! (b) Well done, name! (c) Kabir (d) greet
24. 24.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(1));
25. 25.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(15));
26. 26.🧰 What does return do in a function? (a) repeats the code (b) sends back a value (c) closes the screen (d) deletes the app
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 40;
    }
    show(fee(4) + fee(6));
28. 28.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Arjun")); (a) Welcome, Arjun! (b) greet (c) Welcome, name! (d) Arjun
29. 29.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(2));
30. 30.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(3));
31. 31.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Riya")); (a) Welcome, name! (b) greet (c) Welcome, Riya! (d) Riya
32. 32.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(0));
33. 33.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(8));
34. 34.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(36));
35. 35.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(60, 4));
36. 36.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(4));
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 40;
    }
    show(fee(10) + fee(11));
38. 38.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(16));
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 60;
    }
    show(fee(5) + fee(3));
40. 40.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(36));

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