9.22

import javax.swing.JOptionPane; // import class JOptionPane

public class Addition {
public static void main( String args[] )
{
String firstNumber, // first string entered by user
secondNumber; // second string entered by user
int number1, // first number to add
number2, // second number to add
sum; // sum of number1 and number2

  // read in first number from user as a string
  firstNumber =
     JOptionPane.showInputDialog( "Enter first integer" );

  // read in second number from user as a string
  secondNumber =
     JOptionPane.showInputDialog( "Enter second integer" );

  // convert numbers from type String to type int
  number1 = Integer.parseInt( firstNumber ); 
  number2 = Integer.parseInt( secondNumber );

  // add the numbers
  sum = number1 + number2;

  // display the results
  JOptionPane.showMessageDialog(
     null, "The sum is " + sum, "Results",
     JOptionPane.PLAIN_MESSAGE );

  System.exit( 0 );   // terminate the program

}
}