App Dev Worksheet: Functions

App development lesson 20: Functions · Set 407 · 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 number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(32));
3. 3.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(5));
4. 4.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(36));
5. 5.🧰 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(1) + fee(6));
6. 6.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(19));
7. 7.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(80, 4));
8. 8.🧰 In function tip(bill), what is bill? (a) an event (b) a screen (c) a loop (d) a parameter
9. 9.🧰 What does this code show?
   function greet(name) {
     return "Well done, " + name + "!";
   }
   show(greet("Kabir")); (a) Well done, name! (b) Well done, Kabir! (c) greet (d) Kabir
10. 10.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(1));
11. 11.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya")); (a) Zoya (b) Hi, name! (c) Hi, Zoya! (d) greet
12. 12.🧰 How do you run (call) a function called greet? (a) greet[] (b) greet() (c) #greet (d) run greet
13. 13.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Meera")); (a) Hello, Meera! (b) Meera (c) greet (d) Hello, name!
14. 14.🧰 What does return do in a function? (a) sends back a value (b) closes the screen (c) deletes the app (d) repeats the code
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 20;
    }
    show(fee(4) + fee(4));
16. 16.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(25, 2));
17. 17.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(20, 3));
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 60;
    }
    show(fee(2) + fee(11));
19. 19.🧰 Why write a function? (a) to hide errors (b) to make code longer (c) to slow the app (d) to reuse code
20. 20.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(2));
21. 21.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(6));
22. 22.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(35, 3));
23. 23.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(5));
24. 24.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Arjun")); (a) greet (b) Hi, name! (c) Arjun (d) Hi, Arjun!
25. 25.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Aman")); (a) Aman (b) Hello, Aman! (c) Hello, name! (d) greet
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 60;
    }
    show(fee(9) + fee(2));
27. 27.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 3));
28. 28.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Aman")); (a) Aman (b) Well done, name! (c) greet (d) Well done, Aman!
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 30;
    }
    show(fee(2) + fee(1));
30. 30.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(39));
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 40;
    }
    show(fee(1) + fee(11));
32. 32.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 3));
33. 33.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(12));
34. 34.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(3));
35. 35.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(36));
36. 36.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(100, 4));
37. 37.🧰 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(10) + fee(6));
38. 38.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(9));
39. 39.🧰 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(2) + fee(2));
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(8) + fee(9));

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