/**
 * @(#)PrimeNumberCheck.java
 *
 * PrimeNumberCheck application
 *
 * @author Eric Carr
 * @version 0.8a 2008/3/27
 */
 
import javax.swing.JOptionPane;
public class PrimeNumberCheck {
    public static String userQuestion;
    public static int userNumber = 0;
    public static void main(String[] args) {
    System.out.println("This Program checks whether a number is prime.\nPlease input your number.");
    userQuestion = JOptionPane.showInputDialog(null, "Enter your number so it's primality may be checked.");
    try {
    	userNumber = Integer.parseInt(userQuestion);
    }
    catch (NumberFormatException userGivenNumberPrimeCheckNumFormatEx) {
    	System.err.println("You did not enter a number, you entered" + userQuestion + ".");
    	throw userGivenNumberPrimeCheckNumFormatEx;
    }
    if (userNumber != 0) {
    if (primeChecker.isPrime(userNumber) == true) {
    	System.out.println(userNumber + " is prime.");
    }
    else {
    	System.out.println(userNumber + " is not prime.");
    }
    }
    
    }
    
    
  
}   


//External Class primeChecker


public class primeChecker {
	
	  public static boolean isPrime(int x) {
    int a = 3; //Used to check whether number is prime
    	if ((((Math.pow(a, x))-a)/x) == Math.round(((Math.pow(a, x))-a)/x)) { 
    	
    		return true;
    		
    	}
    	else {
    		return false;
    	}
    	
}
}