App Dev Worksheet: Functions

App development lesson 20: Functions · Set 308 · 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 triple(n) {
     return n * 3;
   }
   show(triple(20));
2. 2.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(30, 3));
3. 3.🧰 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(10));
4. 4.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(35, 2));
5. 5.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(30, 2));
6. 6.🧰 Why write a function? (a) to slow the app (b) to make code longer (c) to reuse code (d) to hide errors
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 30;
   }
   show(fee(9) + fee(2));
8. 8.🧰 What is a function? (a) a list of colours (b) a screen size (c) a type of phone (d) a named block of code
9. 9.🧰 What does this code show?
   function greet(name) {
     return "Hello, " + name + "!";
   }
   show(greet("Riya")); (a) greet (b) Riya (c) Hello, Riya! (d) Hello, name!
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 40;
    }
    show(fee(6) + fee(12));
11. 11.🧰 What does return do in a function? (a) sends back a value (b) repeats the code (c) closes the screen (d) deletes the app
12. 12.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(10));
13. 13.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(35));
14. 14.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Kabir")); (a) Kabir (b) Hi, Kabir! (c) Hi, name! (d) greet
15. 15.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(33));
16. 16.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(37));
17. 17.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(29));
18. 18.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(13));
19. 19.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(4));
20. 20.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Kabir")); (a) Kabir (b) Hello, name! (c) greet (d) Hello, Kabir!
21. 21.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Meera")); (a) greet (b) Welcome, Meera! (c) Meera (d) Welcome, name!
22. 22.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(5));
23. 23.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Zoya")); (a) Welcome, name! (b) greet (c) Zoya (d) Welcome, Zoya!
24. 24.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Aman")); (a) Well done, Aman! (b) Well done, name! (c) greet (d) Aman
25. 25.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(1));
26. 26.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 6));
27. 27.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(50, 4));
28. 28.🧰 How do you run (call) a function called greet? (a) run greet (b) greet() (c) greet[] (d) #greet
29. 29.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya")); (a) Zoya (b) Hi, name! (c) greet (d) Hi, Zoya!
30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(25, 3));
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 30;
    }
    show(fee(12) + fee(1));
32. 32.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(24));
33. 33.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(60, 6));
34. 34.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(6));
35. 35.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(1));
36. 36.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Aman")); (a) greet (b) Hi, Aman! (c) Aman (d) Hi, name!
37. 37.🧰 In function tip(bill), what is bill? (a) a parameter (b) a screen (c) an event (d) a loop
38. 38.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Riya")); (a) Riya (b) Welcome, name! (c) greet (d) Welcome, Riya!
39. 39.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(2));
40. 40.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Riya")); (a) Well done, name! (b) Riya (c) Well done, Riya! (d) greet

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