1  import java.io.File;

  2  import java.io.FileNotFoundException;

  3  import java.io.PrintWriter;

  4  import java.util.Scanner;

  5  

  6  public class PopulationDensity

  7  {

  8     public static void main(String[] args) throws FileNotFoundException

  9     {

 10        // Open input files

 11        Scanner in1 = new Scanner(new File("worldpop.txt")); 

 12        Scanner in2 = new Scanner(new File("worldarea.txt"));

 13  

 14        // Open output file

 15        PrintWriter out = new PrintWriter("world_pop_density.txt"); 

 16  

 17        // Read lines from each file

 18        while (in1.hasNextLine() && in2.hasNextLine())

 19        {

 20           CountryValue population = new CountryValue(in1.nextLine());

 21           CountryValue area = new CountryValue(in2.nextLine());

 22  

 23           // Compute and print the population density

 24           double density = 0;

 25           if (area.getValue() != 0) // Protect against division by zero

 26           {

 27              density = population.getValue() / area.getValue();

 28           }

 29           out.printf("%-40s%15.2f\n", population.getCountry(), density);

 30        }

 31  

 32        in1.close();

 33        in2.close();

 34        out.close();

 35     }

 36  }