Factorial program with a for loop

[spencer.kindt]

I feel like I'm really close... I'm supposed to have some other things configured and use JOptionPane... but I can't get the numbers to output correctly...

import javax.swing.JOptionPane;

public class M3_2E5 {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub

//declare variables		
final int MIN_VALUE = 0;
final int MAX_VALUE = 10;
int factorial = 0;
String response = null;

//show input box
response = JOptionPane.showInputDialog("Please enter a number between 0 and 10: ");

if (response == null){
	JOptionPane.showMessageDialog(null, "You pressed Cancel.");
	System.exit(0);
}
	
if (response.equals("")){
	JOptionPane.showMessageDialog(null, "You didn't enter anything.");
	System.exit(0);
}

factorial = Integer.parseInt(response);

if ((factorial < MIN_VALUE) || (factorial > MAX_VALUE)){
	JOptionPane.showMessageDialog(null, "You entered an invalid number.");
	System.exit(0);
}
		
if (factorial == 0){
	JOptionPane.showMessageDialog(null, "The factorial of the number you entered is 1.");
	System.exit(0);
}


for (int i = 1; i <= MAX_VALUE; i++)
{	
		factorial *= i;
		JOptionPane.showMessageDialog(null, "The factorial of the number you entered is: " + factorial);
	
		
		
	System.exit(0);
	
}
	

	}

}

Thanks a bunch for anyone that helps!!!

[varshakite_21]

Try this.. It's working now..

import javax.swing.JOptionPane;

public class M3_2E5 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

//declare variables     
final int MIN_VALUE = 0;
final int MAX_VALUE = 10;
int factorial = 0;
String response = null;
int i;

//show input box
response = JOptionPane.showInputDialog("Please enter a number between 0 and 10: ");

if (response == null){
    JOptionPane.showMessageDialog(null, "You pressed Cancel.");
    System.exit(0);
}

if (response.equals("")){
    JOptionPane.showMessageDialog(null, "You didn't enter anything.");
    System.exit(0);
}

factorial = Integer.parseInt(response);

if ((factorial < MIN_VALUE) || (factorial > MAX_VALUE)){
    JOptionPane.showMessageDialog(null, "You entered an invalid number.");
    System.exit(0);
}

if (factorial == 0){
    JOptionPane.showMessageDialog(null, "The factorial of the number you entered is 1.");
    System.exit(0);
}

i=factorial-1;
while(i>0)
{   
        factorial=factorial*i;
        i--;
}
        JOptionPane.showMessageDialog(null, "The factorial of the number you entered is: " + factorial);



    System.exit(0); 

    }

}

Thanks!
Varsha.

[varshakite_21]

With for loop:

import javax.swing.JOptionPane;

public class M3_2E5 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

//declare variables     
final int MIN_VALUE = 0;
final int MAX_VALUE = 10;
int factorial = 0;
String response = null;
int i,j;

//show input box
response = JOptionPane.showInputDialog("Please enter a number between 0 and 10: ");

if (response == null){
    JOptionPane.showMessageDialog(null, "You pressed Cancel.");
    System.exit(0);
}

if (response.equals("")){
    JOptionPane.showMessageDialog(null, "You didn't enter anything.");
    System.exit(0);
}

factorial = Integer.parseInt(response);

if ((factorial < MIN_VALUE) || (factorial > MAX_VALUE)){
    JOptionPane.showMessageDialog(null, "You entered an invalid number.");
    System.exit(0);
}

if (factorial == 0){
    JOptionPane.showMessageDialog(null, "The factorial of the number you entered is 1.");
    System.exit(0);
}

j=factorial-1;
for(i=j; i>0; i--)
{   
        factorial=factorial*i;
}
        JOptionPane.showMessageDialog(null, "The factorial of the number you entered is: " + factorial);



    System.exit(0); 

    }

}

[jon.kiparsky]

varshakite - Doing the guy's homework for him isn't much of a help. Much better to lead him to the answer, so he has to make the fixes himself. That way he learns something from the exercise, and you improve your skills as a writer in the process - you might even learn something from having to explain why a thing works as it does.

So, it's better to point out that the problem is in this code block:

for (int i = 1; i <= MAX_VALUE; i++)
{   
        factorial *= i;
        JOptionPane.showMessageDialog(null, "The factorial of the number you entered is: " + factorial);



    System.exit(0);

}

than to just post a "fixed" version of the program.

If you're really feeling generous, you might maybe point out that a for loop with a constant for its limit is not responsive to the user's input, and in any case a for loop including a command to kill the program will only execute once. If you want to go really deep, you might observe that it's generally not necessary to end a program with an exit(0) - this might even cause a problem if you were to try to do some automated testing later.

Nice to see more people answering questions - please keep it up, just give more suggestions than code.

(also, please put your code in CODE tags for readability!)

[spencer.kindt]

Thank you all for your help... I was able to figure it out. Sometimes it helps to see an example of something similar that works so that the logic is easier understood...