/* Program that reads integer values from a file and adds them up.
 *
 * Carsten Butz, October 2002
 */

import java.io.*;
import java.util.StringTokenizer;

class AddNumbers{

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

    /* Print an error message if no file name is given and exit. */
    if(args.length ==0){
      System.out.println("Usage: java AddNumbers filename");
      System.exit(0);
    }

    /* Start the 'real' program. */
    int sum = 0;
    String line = null;

    /* Open the file for reading. */
    BufferedReader input = new BufferedReader(new FileReader(args[0]));

    /* Read the first line. */
    line = input.readLine();

    /* For non-empty lines do the following: */
    while(line != null){
      System.out.println(line);  // print out line as a check
      
      /* Create a new String Tokenizer. Tokens a separated by spaces. */
      StringTokenizer st = new StringTokenizer(line, " "); 

      /* The following loop splits the StringTokenizer into individual tokens
       * (while they are available), and tries to parse an integer value from 
       * each individual token. If this fails an error message is printed.
       */
      while(st.hasMoreTokens()){

	try{
	  sum = sum + Integer.parseInt(st.nextToken());
	}
	catch(NumberFormatException nfe)
	  {
	    System.out.println("The file contained a non-integer value!");
	  }
	
      }
      /* The line is handled and we can read the next line. */
      line = input.readLine();
    }
    
    System.out.println("The sum is " + sum + ".");
    
  }
  
}