Thread: Read txt file into array and create new output.

What I need to do is create a class that creates a text file of an array. (Which I have posted Below)

What I need help with

Once that file is created I need to create a class that reads the numbers that were created and then multiplies all the numbers by the number at position [0][0]. Then creates a new .txt file and puts them in there.

Ex:
Original numbers
5 6 3 4

Output needs to be
25 30 15 20

I have a class that reads the numbers and just prints them out. I cant figure out how to read the numbers and do anything with them.


Code that creates file with array of numbers.....

import java.io.*;
import java.util.Random;
public class Output
{
 public static void main(String args[])
  {
	 final int rowW = 2;
	 final int colH = 4;
 
	 Random rand = new Random();
	 int [][] array1 = new int [rowW][colH];
 
	 for (int row = 0; row < array1.length; row++) {
 
	     for (int col = 0; col < array1[row].length; col++) {
 
	             array1[row][col] = rand.nextInt(10);
 
	          }
 
	      }
 
  try{
	  FileWriter  fStream;
	   PrintWriter  myStream;
	   fStream = new FileWriter( "randomarray.txt");
	   myStream = new PrintWriter( fStream );
 
	   int l= array1.length;
 
	   for(int i = 0; i < l; i++) {
	   for(int j = 0; j <= l; j++) {
	   myStream.print( " "+ array1[i][j] );
	   }
	   }
	   myStream.flush();
	   myStream.close();
	}
	catch (IOException e)  {
	   System.out.println("I/O exception" );
	}
}
 
}

Just reads the array and prints it out. I need it to read the numbers and then be able to multiply them and create a new file with multiplied numbers. (I could just add them to the bottom of the original file if that is possible)

 
import java.io.*;
class input {
    public static void main(String[] args) {
    	try {
    		   FileReader  fReader;
    		   BufferedReader  reader;
    		   int  charAsInt;
    		   fReader = new FileReader("randomarray.txt");
    		   reader = new BufferedReader( fReader );
    		   charAsInt = reader.read();
    		   while ( charAsInt != -1 )   {
    		      System.out.print( (char)charAsInt); 
    		      charAsInt = reader.read();
    		   }
    		   reader.close();
    		}
    		catch (IOException e)  {
    		   System.out.println( "I/O exception" );
    		}
 
 
 
 
    }
}

Thanks in advance for any help