App Dev Worksheet: Functions

App development lesson 20: Functions · Set 610 · 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.🧰 Why write a function? (a) to slow the app (b) to reuse code (c) to hide errors (d) to make code longer
2. 2.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(28));
3. 3.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(80, 6));
4. 4.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(55, 5));
5. 5.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(10, 4));
6. 6.🧰 What does return do in a function? (a) repeats the code (b) sends back a value (c) deletes the app (d) closes the screen
7. 7.🧰 In function tip(bill), what is bill? (a) an event (b) a parameter (c) a loop (d) a screen
8. 8.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(80, 3));
9. 9.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(4) + points(2));
10. 10.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya")); (a) greet (b) Hello, Riya! (c) Riya (d) Hello, name!
11. 11.🧰 What is a function? (a) a type of phone (b) a named block of code (c) a screen size (d) a list of colours
12. 12.🧰 How do you run (call) a function called greet? (a) greet[] (b) #greet (c) greet() (d) run greet
13. 13.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(5));
14. 14.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Kabir")); (a) greet (b) Well done, Kabir! (c) Kabir (d) Well done, name!
15. 15.🧰 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
16. 16.🧰 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));
17. 17.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(29));
18. 18.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(16));
19. 19.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(90, 4));
20. 20.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(23));
21. 21.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(5));
22. 22.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(25));
23. 23.🧰 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(1));
24. 24.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(15));
25. 25.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 6));
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 20;
    }
    show(fee(4) + fee(8));
27. 27.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(1));
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(11) + fee(1));
29. 29.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(85, 4));
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 30;
    }
    show(fee(7) + fee(12));
31. 31.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(0));
32. 32.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Meera")); (a) greet (b) Well done, Meera! (c) Meera (d) Well done, name!
33. 33.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Aman")); (a) Aman (b) Hi, Aman! (c) Hi, name! (d) greet
34. 34.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(60, 6));
35. 35.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Meera")); (a) Hi, Meera! (b) greet (c) Hi, name! (d) Meera
36. 36.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(37));
37. 37.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Kabir")); (a) greet (b) Welcome, Kabir! (c) Welcome, name! (d) Kabir
38. 38.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(5));
39. 39.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Zoya")); (a) Zoya (b) Well done, name! (c) greet (d) Well done, Zoya!
40. 40.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(5));

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