App Dev Worksheet: Functions

App development lesson 20: Functions · Set 418 · 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(90, 5));
2. 2.🧰 In function tip(bill), what is bill? (a) an event (b) a screen (c) a loop (d) a parameter
3. 3.🧰 How do you run (call) a function called greet? (a) #greet (b) greet[] (c) run greet (d) greet()
4. 4.🧰 What does return do in a function? (a) sends back a value (b) closes the screen (c) deletes the app (d) repeats the code
5. 5.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(80, 2));
6. 6.🧰 Why write a function? (a) to make code longer (b) to hide errors (c) to reuse code (d) to slow the app
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 50;
   }
   show(fee(11) + fee(10));
8. 8.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(22));
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(12) + fee(6));
10. 10.🧰 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(12));
11. 11.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(4));
12. 12.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(1));
13. 13.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(3));
14. 14.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 2));
15. 15.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Riya")); (a) greet (b) Riya (c) Welcome, name! (d) Welcome, Riya!
16. 16.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(17));
17. 17.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(19));
18. 18.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(23));
19. 19.🧰 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(11));
20. 20.🧰 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(4) + fee(5));
21. 21.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(4));
22. 22.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(35));
23. 23.🧰 What is a function? (a) a screen size (b) a list of colours (c) a named block of code (d) a type of phone
24. 24.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(3));
25. 25.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 4));
26. 26.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(29));
27. 27.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(45, 2));
28. 28.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(4));
29. 29.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(85, 4));
30. 30.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(31));
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 50;
    }
    show(fee(1) + fee(7));
32. 32.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 4));
33. 33.🧰 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(8));
34. 34.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(6));
35. 35.🧰 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(10) + fee(3));
36. 36.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(14));
37. 37.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(2));
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 50;
    }
    show(fee(1) + fee(4));
39. 39.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Riya")); (a) Riya (b) greet (c) Hi, name! (d) Hi, Riya!
40. 40.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(40));

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