// Fig. 7.9: PassArray.java
// Passing arrays and individual array elements to methods.
import javax.swing.*;

public class PassArray {

  public static void main(String[] args)
  {
    JTextArea outputArea = new JTextArea();

    int array[] = { 1, 2, 3, 4, 5 };

    String output = "Effects of passing entire array by reference:\n" +
                    "The values of the original array are:\n";

    // append original array elements to String output
    for ( int counter = 0; counter < array.length; counter++ )
      output += "   " + array[ counter ];

    modifyArray( array );  // array passed by reference

    output += "\n\nThe values of the modified array are:\n";

    // append modified array elements to String output
    for ( int counter = 0; counter < array.length; counter++ )
      output += "   " + array[ counter ];

    output += "\n\nEffects of passing array element by value:\n" +
              "array[3] before modifyElement: " + array[ 3 ];

    modifyElement( array[ 3 ] );  // attempt to modify array[ 3 ]

    output += "\narray[3] after modifyElement: " + array[ 3 ];
    outputArea.setText( output );

    JOptionPane.showMessageDialog( null, outputArea,
                                   "PassArray Results",
                                   JOptionPane.INFORMATION_MESSAGE );

    System.exit( 0 );

  } // end method main

  // multiply each element of an array by 2
  public static void modifyArray( int array2[] )
  {
    for ( int counter = 0; counter < array2.length; counter++ )
      array2[ counter ] *= 2;
  }

  // multiply argument by 2
  public static void modifyElement( int element )
  {
    element *= 2;
  }

} // end class PassArray