App Dev Worksheet: Functions

App development lesson 20: Functions · Set 807 · 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) sends back a value (c) deletes the app (d) closes the screen
2. 2.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(6));
3. 3.🧰 Why write a function? (a) to slow the app (b) to make code longer (c) to reuse code (d) to hide errors
4. 4.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(18));
5. 5.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(15));
6. 6.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(7));
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(12));
8. 8.🧰 What does this code show?
   function greet(name) {
     return "Hello, " + name + "!";
   }
   show(greet("Riya")); (a) Hello, name! (b) Hello, Riya! (c) Riya (d) greet
9. 9.🧰 What is a function? (a) a type of phone (b) a list of colours (c) a named block of code (d) a screen size
10. 10.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(5));
11. 11.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(5));
12. 12.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(9));
13. 13.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Meera")); (a) greet (b) Hello, Meera! (c) Hello, name! (d) Meera
14. 14.🧰 In function tip(bill), what is bill? (a) a loop (b) a screen (c) a parameter (d) an event
15. 15.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Aman")); (a) greet (b) Well done, Aman! (c) Aman (d) Well done, name!
16. 16.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 6));
17. 17.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(1));
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 50;
    }
    show(fee(2) + fee(3));
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 20;
    }
    show(fee(8) + fee(8));
20. 20.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(3));
21. 21.🧰 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(2));
22. 22.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(3));
23. 23.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(26));
24. 24.🧰 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(1));
25. 25.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(3));
26. 26.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(65, 6));
27. 27.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 5));
28. 28.🧰 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(8));
29. 29.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(7));
30. 30.🧰 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(9) + fee(2));
31. 31.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(1));
32. 32.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(11));
33. 33.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(31));
34. 34.🧰 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(5) + fee(3));
35. 35.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Riya")); (a) Riya (b) Welcome, name! (c) Welcome, Riya! (d) greet
36. 36.🧰 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
37. 37.🧰 How do you run (call) a function called greet? (a) #greet (b) greet[] (c) run greet (d) greet()
38. 38.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(3));
39. 39.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(85, 3));
40. 40.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(15, 4));

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