App Dev Worksheet: Functions

App development lesson 20: Functions · Set 863 · 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) deletes the app (c) closes the screen (d) sends back a value
2. 2.🧰 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(6) + fee(1));
3. 3.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(5) + points(0));
4. 4.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(5) + points(5));
5. 5.🧰 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(7));
6. 6.🧰 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(7));
7. 7.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(28));
8. 8.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(7));
9. 9.🧰 What does this code show?
   function greet(name) {
     return "Well done, " + name + "!";
   }
   show(greet("Meera")); (a) Meera (b) Well done, name! (c) Well done, Meera! (d) greet
10. 10.🧰 What is a function? (a) a type of phone (b) a named block of code (c) a list of colours (d) a screen size
11. 11.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(5));
12. 12.🧰 How do you run (call) a function called greet? (a) run greet (b) greet() (c) greet[] (d) #greet
13. 13.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(32));
14. 14.🧰 In function tip(bill), what is bill? (a) a screen (b) an event (c) a parameter (d) a loop
15. 15.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(29));
16. 16.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya")); (a) Zoya (b) Hi, Zoya! (c) Hi, name! (d) greet
17. 17.🧰 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(3) + fee(2));
18. 18.🧰 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(3) + fee(11));
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 40;
    }
    show(fee(11) + fee(10));
20. 20.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(6));
21. 21.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(2));
22. 22.🧰 Why write a function? (a) to reuse code (b) to slow the app (c) to hide errors (d) to make code longer
23. 23.🧰 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(6));
24. 24.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(22));
25. 25.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(0));
26. 26.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(75, 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(12) + fee(12));
28. 28.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 2));
29. 29.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(28));
30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(65, 3));
31. 31.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(2));
32. 32.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(95, 3));
33. 33.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(29));
34. 34.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Aman")); (a) Hello, Aman! (b) Aman (c) Hello, name! (d) greet
35. 35.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Kabir")); (a) Hello, Kabir! (b) Hello, name! (c) greet (d) Kabir
36. 36.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Kabir")); (a) greet (b) Welcome, name! (c) Kabir (d) Welcome, Kabir!
37. 37.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(45, 4));
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 30;
    }
    show(fee(11) + fee(9));
39. 39.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(35, 2));
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 40;
    }
    show(fee(10) + fee(3));

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