4-21 FileSum2

Post date: Mar 5, 2014 10:30:17 AM

//This version of the program confirms that the Numbers.txt file exists before opening it.

package filesum2;

import java.io.*;

import java.util.Scanner;

public class FileSum2

{

    public static void main(String[] args)throws IOException

    {

           double sum = 0.0; // Accumulator, initialized to 0

           // Make sure the file exists.

           File file = new File( "Numbers.txt");

           if (!file.exists())

           {

               System.out.println("The file Numbers.txt is not found.");

               System.exit(0);

           }

           // Open the file for reading.

           Scanner inputFile = new Scanner(file);

           // Read all of the values from the file

           // and calculate their total.

           while (inputFile.hasNext())

           {

               // Read a value from the file.

               double number = inputFile.nextDouble();

               // Add the number to sum.

               sum = sum + number;

           }

           // Close the file.

           inputFile.close();

           // Display the sum of the numbers.

           System.out.println("The sum of the numbers in Numbers.txt is " + sum);

    }  

}