App Dev Worksheet: Functions

App development lesson 20: Functions · Set 240 · 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 is a function? (a) a screen size (b) a type of phone (c) a named block of code (d) a list of colours
2. 2.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(4) + points(0));
3. 3.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(40, 6));
4. 4.🧰 How do you run (call) a function called greet? (a) run greet (b) greet[] (c) #greet (d) greet()
5. 5.🧰 What does this code show?
   function greet(name) {
     return "Welcome, " + name + "!";
   }
   show(greet("Arjun")); (a) Welcome, name! (b) Arjun (c) Welcome, Arjun! (d) greet
6. 6.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(2) + points(2));
7. 7.🧰 Why write a function? (a) to reuse code (b) to hide errors (c) to slow the app (d) to make code longer
8. 8.🧰 What does this code show?
   function greet(name) {
     return "Hello, " + name + "!";
   }
   show(greet("Aman")); (a) Hello, name! (b) Aman (c) Hello, Aman! (d) greet
9. 9.🧰 What does this code show?
   function greet(name) {
     return "Welcome, " + name + "!";
   }
   show(greet("Zoya")); (a) greet (b) Welcome, Zoya! (c) Zoya (d) Welcome, name!
10. 10.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(3));
11. 11.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 3));
12. 12.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(15, 2));
13. 13.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(23));
14. 14.🧰 What does return do in a function? (a) deletes the app (b) sends back a value (c) closes the screen (d) repeats the code
15. 15.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 2));
16. 16.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Meera")); (a) greet (b) Meera (c) Well done, name! (d) Well done, Meera!
17. 17.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(4));
18. 18.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Meera")); (a) Welcome, name! (b) Meera (c) greet (d) Welcome, Meera!
19. 19.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya")); (a) greet (b) Zoya (c) Hi, name! (d) Hi, Zoya!
20. 20.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya")); (a) Hello, name! (b) Hello, Riya! (c) greet (d) Riya
21. 21.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(14));
22. 22.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(4));
23. 23.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(29));
24. 24.🧰 In function tip(bill), what is bill? (a) a loop (b) a screen (c) an event (d) a parameter
25. 25.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(6));
26. 26.🧰 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(5) + fee(1));
27. 27.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(0));
28. 28.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(24));
29. 29.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(0));
30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(25, 3));
31. 31.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 4));
32. 32.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(5));
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(8) + fee(3));
34. 34.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(37));
35. 35.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(35));
36. 36.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(40, 2));
37. 37.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(20, 6));
38. 38.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(4));
39. 39.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(7));
40. 40.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(24));

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