App Dev Worksheet: Functions

App development lesson 20: Functions · Set 101 · 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 double(n) {
     return n * 2;
   }
   show(double(30));
2. 2.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(80, 4));
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 30;
   }
   show(fee(11) + fee(9));
4. 4.🧰 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(4) + fee(11));
5. 5.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(6));
6. 6.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(4) + points(0));
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 60;
   }
   show(fee(9) + fee(9));
8. 8.🧰 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(8) + fee(3));
9. 9.🧰 What does this code show?
   function greet(name) {
     return "Hi, " + name + "!";
   }
   show(greet("Riya")); (a) Hi, Riya! (b) greet (c) Hi, name! (d) Riya
10. 10.🧰 What is a function? (a) a screen size (b) a list of colours (c) a type of phone (d) a named block of code
11. 11.🧰 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(7) + fee(3));
12. 12.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(95, 4));
13. 13.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(15));
14. 14.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(2));
15. 15.🧰 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(6) + fee(12));
16. 16.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(1));
17. 17.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(16));
18. 18.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(18));
19. 19.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(40, 5));
20. 20.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(1));
21. 21.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(90, 2));
22. 22.🧰 How do you run (call) a function called greet? (a) run greet (b) #greet (c) greet[] (d) greet()
23. 23.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(20));
24. 24.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(3));
25. 25.🧰 In function tip(bill), what is bill? (a) a screen (b) a parameter (c) an event (d) a loop
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(1) + fee(12));
27. 27.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 3));
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 50;
    }
    show(fee(6) + fee(9));
29. 29.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(2));
30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(15, 6));
31. 31.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(3));
32. 32.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(10));
33. 33.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 4));
34. 34.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya")); (a) greet (b) Zoya (c) Hi, Zoya! (d) Hi, name!
35. 35.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Aman")); (a) Aman (b) Welcome, Aman! (c) greet (d) Welcome, name!
36. 36.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 5));
37. 37.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(26));
38. 38.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Aman")); (a) Aman (b) greet (c) Hello, name! (d) Hello, Aman!
39. 39.🧰 What does return do in a function? (a) repeats the code (b) sends back a value (c) closes the screen (d) deletes the app
40. 40.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Aman")); (a) Hi, Aman! (b) greet (c) Aman (d) Hi, name!

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