App Dev Worksheet: Functions

App development lesson 20: Functions · Set 256 · 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.🧰 Why write a function? (a) to hide errors (b) to reuse code (c) to make code longer (d) to slow the app
2. 2.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(40, 5));
3. 3.🧰 What is a function? (a) a list of colours (b) a named block of code (c) a screen size (d) a type of phone
4. 4.🧰 What does this code show?
   function greet(name) {
     return "Hi, " + name + "!";
   }
   show(greet("Riya")); (a) Riya (b) Hi, Riya! (c) Hi, name! (d) greet
5. 5.🧰 What does this code show?
   function greet(name) {
     return "Hi, " + name + "!";
   }
   show(greet("Aman")); (a) Hi, name! (b) Aman (c) greet (d) Hi, Aman!
6. 6.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(5));
7. 7.🧰 What does return do in a function? (a) deletes the app (b) sends back a value (c) repeats the code (d) closes the screen
8. 8.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(30));
9. 9.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(4));
10. 10.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Arjun")); (a) greet (b) Arjun (c) Hello, name! (d) Hello, Arjun!
11. 11.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(35, 3));
12. 12.🧰 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(9) + fee(11));
13. 13.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(21));
14. 14.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(95, 5));
15. 15.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(39));
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(4) + fee(10));
17. 17.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 2));
18. 18.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(90, 6));
19. 19.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(0));
20. 20.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Kabir")); (a) greet (b) Welcome, Kabir! (c) Welcome, name! (d) Kabir
21. 21.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(1));
22. 22.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(25));
23. 23.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya")); (a) greet (b) Hi, name! (c) Zoya (d) Hi, Zoya!
24. 24.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Kabir")); (a) Hi, name! (b) Kabir (c) Hi, Kabir! (d) greet
25. 25.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Kabir")); (a) Kabir (b) greet (c) Hello, name! (d) Hello, Kabir!
26. 26.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(4));
27. 27.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Aman")); (a) Welcome, Aman! (b) greet (c) Aman (d) Welcome, name!
28. 28.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 4));
29. 29.🧰 How do you run (call) a function called greet? (a) greet[] (b) greet() (c) #greet (d) run greet
30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(60, 2));
31. 31.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(40));
32. 32.🧰 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(12));
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 40;
    }
    show(fee(6) + fee(12));
34. 34.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(8));
35. 35.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(0));
36. 36.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Zoya")); (a) Zoya (b) Well done, name! (c) Well done, Zoya! (d) greet
37. 37.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Arjun")); (a) Hi, Arjun! (b) greet (c) Arjun (d) Hi, name!
38. 38.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(36));
39. 39.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 2));
40. 40.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Riya")); (a) Riya (b) greet (c) Welcome, name! (d) Welcome, Riya!

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