package class4_1_CheckingJOptionPane; // Josiah Yoder, MSOE, 28 September 2015

import javax.swing.*;
import java.util.Scanner;

public class CheckingJOptionPane {
    public static void main(String[] args) {
        String numberStr = "";
        boolean goodStr = false;
        Scanner stringScanner = null;
        while(numberStr != null && !goodStr) {
            numberStr = JOptionPane.showInputDialog("Welcome to the Square-root computer.\nPlease enter a number: ");
            if(numberStr != null) {
                stringScanner = new Scanner(numberStr);
                goodStr = stringScanner.hasNextDouble();
            }
        }
        if(numberStr == null) {
            JOptionPane.showMessageDialog(null,"Thank you for using the program.");
        } else {
            double number = stringScanner.nextDouble();
            double root = Math.sqrt(number); // What to put here?
            JOptionPane.showMessageDialog(null, "The square root is: " + root);
        }
    }
}