App Dev Worksheet: Functions

App development lesson 20: Functions · Set 257 · 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 hide errors (c) to make code longer (d) to reuse code
2. 2.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(17));
3. 3.🧰 What does return do in a function? (a) deletes the app (b) sends back a value (c) closes the screen (d) repeats the code
4. 4.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(1) + points(3));
5. 5.🧰 In function tip(bill), what is bill? (a) a loop (b) an event (c) a screen (d) a parameter
6. 6.🧰 How do you run (call) a function called greet? (a) greet[] (b) greet() (c) run greet (d) #greet
7. 7.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(4) + points(3));
8. 8.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(19));
9. 9.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(50, 4));
10. 10.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(85, 4));
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 20;
    }
    show(fee(12) + fee(6));
12. 12.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(22));
13. 13.🧰 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(5) + fee(9));
14. 14.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(4));
15. 15.🧰 What is a function? (a) a list of colours (b) a type of phone (c) a screen size (d) a named block of code
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 30;
    }
    show(fee(8) + fee(3));
17. 17.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(21));
18. 18.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Riya")); (a) greet (b) Hi, name! (c) Hi, Riya! (d) Riya
19. 19.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(15, 4));
20. 20.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 2));
21. 21.🧰 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(9) + fee(1));
22. 22.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(1));
23. 23.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(38));
24. 24.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(0));
25. 25.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(4));
26. 26.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Zoya")); (a) Zoya (b) Welcome, name! (c) greet (d) Welcome, Zoya!
27. 27.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(55, 6));
28. 28.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Zoya")); (a) Hello, name! (b) Zoya (c) Hello, Zoya! (d) greet
29. 29.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Arjun")); (a) greet (b) Hello, Arjun! (c) Arjun (d) Hello, name!
30. 30.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(1));
31. 31.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(2));
32. 32.🧰 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(6));
33. 33.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Riya")); (a) Welcome, name! (b) greet (c) Riya (d) Welcome, Riya!
34. 34.🧰 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(6) + fee(2));
35. 35.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(0));
36. 36.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Meera")); (a) greet (b) Hello, Meera! (c) Meera (d) Hello, name!
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 30;
    }
    show(fee(9) + fee(5));
38. 38.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(6));
39. 39.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(35, 3));
40. 40.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(2));

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