public class Parameters {

    public static void main (String[] argv)
    {
        int a = 1;
        int b = 2;
        System.out.println ("BEFORE: a=" + a + " b=" + b);

        swap (a, b);
        System.out.println ("AFTER:  a=" + a + " b=" + b);
    }

    static void swap (int x, int y)
    {
        System.out.println ("  BEFORE: x=" + x + " y=" + y);
        int temp = x;
        x = y;
        y = temp;
        System.out.println ("  AFTER:  x=" + x + " y=" + y);
    }

}