// Execise 5.16 Solution: Pi.java
// Program calculates Pi from the infinite series.

// Java extension packages
import javax.swing.*;

public class Pi {

   //method main begins execution of Java application
   public static void main( String args[] )
   {
      double piValue = 0, number = 4.0, denominator = 1.0;
      int accuracy = 400;

      JTextArea outputArea = new JTextArea( 17, 40 );
      JScrollPane scroller = new JScrollPane( outputArea );

      String output = "Accuracy: \n" + accuracy;
      output += "\nTerm\t\tPi\n";

      for ( int term = 1; term <= accuracy; term++ ) {

         if ( term % 2 != 0 )
            piValue += number / denominator;

         else
            piValue -= number / denominator;

         output += "\n" + term + "\t\t" + piValue;
         denominator += 2.0;
      }

      outputArea.setText( output );

      JOptionPane.showMessageDialog( null, scroller, "PI",
         JOptionPane.INFORMATION_MESSAGE );

      System.exit( 0 );

   }  // end method main

}  // end class Pi