App Dev Worksheet: Functions

App development lesson 20: Functions · Set 200 · 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 total(price, qty) {
     return price * qty;
   }
   show(total(65, 4));
2. 2.🧰 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(4));
3. 3.🧰 In function tip(bill), what is bill? (a) a loop (b) a parameter (c) a screen (d) an event
4. 4.🧰 What does this code show?
   function greet(name) {
     return "Welcome, " + name + "!";
   }
   show(greet("Arjun")); (a) greet (b) Arjun (c) Welcome, name! (d) Welcome, Arjun!
5. 5.🧰 What does return do in a function? (a) closes the screen (b) repeats the code (c) deletes the app (d) sends back a value
6. 6.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(70, 6));
7. 7.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(80, 5));
8. 8.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(40, 6));
9. 9.🧰 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));
10. 10.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 6));
11. 11.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(85, 6));
12. 12.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(21));
13. 13.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Aman")); (a) greet (b) Aman (c) Hello, name! (d) Hello, Aman!
14. 14.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Aman")); (a) Aman (b) greet (c) Well done, name! (d) Well done, Aman!
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 60;
    }
    show(fee(1) + fee(1));
16. 16.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(100, 3));
17. 17.🧰 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(8));
18. 18.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(37));
19. 19.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Kabir")); (a) Kabir (b) greet (c) Welcome, name! (d) Welcome, Kabir!
20. 20.🧰 What is a function? (a) a list of colours (b) a named block of code (c) a type of phone (d) a screen size
21. 21.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(4));
22. 22.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(12));
23. 23.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(19));
24. 24.🧰 Why write a function? (a) to hide errors (b) to slow the app (c) to make code longer (d) to reuse code
25. 25.🧰 How do you run (call) a function called greet? (a) run greet (b) greet[] (c) #greet (d) greet()
26. 26.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 5));
27. 27.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(22));
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 20;
    }
    show(fee(7) + fee(8));
29. 29.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(1));
30. 30.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(24));
31. 31.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(32));
32. 32.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Kabir")); (a) Well done, name! (b) Kabir (c) greet (d) Well done, Kabir!
33. 33.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(60, 2));
34. 34.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(3));
35. 35.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(5));
36. 36.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(2));
37. 37.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(26));
38. 38.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(50, 3));
39. 39.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(3));
40. 40.🧰 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(10) + fee(3));

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