java from control structures through objects 6th\' Programming challenge number

Question

java from control structures through objects 6th'

Programming challenge number 6)File Array Class

Design a class that has a static method named writeArray. The method should take two arguments: the name of a file and a reference to an int array. The file should be opened as a binary file, the contents of the array should be written to the file, and then the file should be closed.

Write a second method in the class named readArray. The method should take two arguments: the name of a file and a reference to an int array. The file should be opened, data should be read from the file and stored in the array, and then the file should be closed.

Demonstrate both methods in a program, Use comments through the code.

Explanation / Answer

import java.io.*;
public class FileArray
{
  
   public static void writeArray(int[] num, String fileName) throws IOException
   {
       //Create binary output objects
       FileOutputStream fstream = new FileOutputStream(fileName);
       DataOutputStream outputFile = new DataOutputStream(fstream);
      
       System.out.println("Writing to the file.");

       //Write the array elements to the binary file
       for (int i = 0; i < num.length; i++)
           outputFile.writeInt(num[i]);

       //Close the file
       outputFile.close();
       System.out.println("Succesfully wrote to the file");

   }

   public static void readArray(int[] num, String fileName) throws IOException
   {
       int i = 0;
       boolean endOfFile = false;

       System.out.println("Reading numbers from the file: ");
       //Create binary output objects
       FileInputStream fstream = new FileInputStream(fileName);
       DataInputStream inputFile = new DataInputStream(fstream);

       while (!endOfFile)
       {
           try
           {
               num[i] = inputFile.readInt();
               i++;
               System.out.println(i + " ");
           }
           catch (EOFException e)
           {
               endOfFile = true;
           }
       }
      
       //Close the file
       inputFile.close();
       System.out.println("Succesfully closed the file.");
   }
}

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