Question: Here is my Perl code

```
use POSIX;

my @arr = split(/\\n\\n/, $content);

my $len = length @arr;

$len = $len / 2;

my $b = round($len) - 1;

```

At the top of my script I have `use POSIX`. I once had `use Math::Round` but that didn't work.

I'm trying to use the `round` function but the page keeps breaking when I call it.

Answer: 
You have to actually call `changeToFahrenheit` from your main method, so your code is:

```
import java.util.Scanner;
public class HelloWorld{

     public static void main(String []args){
          changeToFahrenheit();
     }

    public static double changeToFahrenheit(){

        Scanner reader = new Scanner(System.in);
        System.out.println("Enter a number between 0-20: ");
        double celsius = reader.nextInt();
        double fahrenheit = (9/5) * celsius +32;

        System.out.println(fahrenheit);
        return fahrenheit;
    }
}

```

To use a function, you must call a function (This is like the equivalent of the `Main` function in C#). By the way, you cannot do `9/5`, since integer division will result in an integer, `1`. Try `9.0/5.0` for the computation.
* As the method is static method you could call the method with out creating an object.
* reader.nextInt(); // This returns integer .. so store it in integer.
* you don't have to return value unless you have other methods which reuses this value returned.