App Dev Worksheet: Functions

App development lesson 20: Functions · Set 224 · 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 list of colours (c) a named block of code (d) a type of phone
2. 2.🧰 What does this code show?
   function greet(name) {
     return "Welcome, " + name + "!";
   }
   show(greet("Arjun")); (a) Arjun (b) Welcome, name! (c) greet (d) Welcome, Arjun!
3. 3.🧰 Why write a function? (a) to hide errors (b) to slow the app (c) to make code longer (d) to reuse code
4. 4.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(7));
5. 5.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(5));
6. 6.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(2) + points(4));
7. 7.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(8));
8. 8.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(2) + points(2));
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 20;
   }
   show(fee(4) + fee(10));
10. 10.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(22));
11. 11.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(65, 6));
12. 12.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(35, 3));
13. 13.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(3));
14. 14.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(32));
15. 15.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(28));
16. 16.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(38));
17. 17.🧰 How do you run (call) a function called greet? (a) #greet (b) run greet (c) greet() (d) greet[]
18. 18.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(15, 6));
19. 19.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(32));
20. 20.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 6));
21. 21.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Aman")); (a) Well done, name! (b) Aman (c) greet (d) Well done, Aman!
22. 22.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(4));
23. 23.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Arjun")); (a) Hello, name! (b) Arjun (c) greet (d) Hello, Arjun!
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 60;
    }
    show(fee(10) + fee(12));
25. 25.🧰 What does return do in a function? (a) closes the screen (b) sends back a value (c) deletes the app (d) repeats the code
26. 26.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(50, 3));
27. 27.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(10));
28. 28.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Kabir")); (a) Hello, name! (b) Kabir (c) greet (d) Hello, Kabir!
29. 29.🧰 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(3) + fee(5));
30. 30.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Riya")); (a) Riya (b) Hi, name! (c) greet (d) Hi, Riya!
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(8) + fee(2));
32. 32.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(0));
33. 33.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Aman")); (a) Hello, name! (b) Aman (c) greet (d) Hello, Aman!
34. 34.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 2));
35. 35.🧰 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(7) + fee(3));
36. 36.🧰 In function tip(bill), what is bill? (a) an event (b) a parameter (c) a loop (d) a screen
37. 37.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(60, 5));
38. 38.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya")); (a) Hello, name! (b) Riya (c) greet (d) Hello, Riya!
39. 39.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Zoya")); (a) greet (b) Well done, Zoya! (c) Well done, name! (d) Zoya
40. 40.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Meera")); (a) Hi, Meera! (b) Hi, name! (c) Meera (d) greet

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