// Find all perfect numbers less than 
// or equal to then entered upper bound.
// Use a method sumFactors that finds the sum of
// the factors of the input.

import javax.swing.JOptionPane;
    
public class Perfect2
{
    public static void main(String[ ] argv)
    {
        int upperBound, n;

        upperBound = Integer.parseInt(JOptionPane.showInputDialog(
                "Enter upper bound for perfect number search"));
    
        for(n = 2; n <= upperBound; n++)
            if (n == sumFactors(n))
                System.out.println(n);
    }

    public static int sumFactors(int n)
    {
        int sum = 0;
        for(int factor = 1; factor <= n / 2; factor++)
            if (n % factor == 0)
                sum += factor;
        return sum;
    }
}


// Prompt of input dialog:
Upper bound for perfect number search:

// Sample input to input dialog:
10000

// Output in Terminal Window:
6
28
496
8128