//Dialog.java
//demo of JOptionPane input and output dialog windows

import javax.swing.*;     //for JOptionPane

public class Dialog {       //extends JApplet {
    //public void init () {
    public static void main (String[] argv) {

	String name, input;
	int age;
	double radius, circumference, area;

	//showInputDialog returns a String, 
	//assign it to a String variable (object):
	name = JOptionPane.showInputDialog( "Enter your name please" );
	
	//showMessageDialog displays a string
	JOptionPane.showMessageDialog( null, "Welcome: " + name );
	//null must be the first argument
	//2nd argument is string, here with string concatenation 

	input = JOptionPane.showInputDialog( "Enter your age in years" );
	//to input an int, need to convert String to int:
	age = Integer.parseInt( input );    //extremely finicky
	age++;   
	JOptionPane.showMessageDialog( null, 
	    "On your next birthday you will be: " + age );

	input = JOptionPane.showInputDialog( "Enter radius of a circle" );
	//to input a double, need to convert String to double:
	radius = Double.parseDouble( input );
	
	circumference = 2 * radius * Math.PI;
	area = radius*radius * Math.PI;
	JOptionPane.showMessageDialog( null, 
	    "Circumference=" + circumference +
	    "  Area=" + area);
    }
}